Mogontiacum

City map of Mogontiacum in the period 1st century BCE to 5th century CE
Interactive map of Mogontiacum
Alternative name	Moguntiacum
Location	Mainz, Germany
Type	Roman city
History
Founded	13/12 BCE
Periods	Roman Empire

Mogontiacum (alsoMoguntiacum) is theLatinname of today's city ofMainz, which it bore during its almost 500 years as part of theRoman Empire.Mogontiacum had its origins in thelegionary camp built byDrusus in 13/12 BCE, which was strategically located on ahill [de] above theRhine and opposite the mouth of theMain on theRoman Rhine valley road [de].

The civilian settlements (vici) in the vicinity of the camp, which spread down the Rhine, quickly grew together to form a larger, urbanised settlement. However, unlikeColonia Claudia Ara Agrippinensium (Cologne) orAugusta Treverorum (Trier),Mogontiacum was primarily a military centre until the second half of the 4th century and was apparently not acolonia either. As a result, the city never had the urban character of the other large Roman cities in Germany. Nevertheless, several monumental buildings were also erected here, asMogontiacum was the provincial capital of the Roman province ofGermania Superior with the seat of the governor as of the year 90 at the latest. After the middle of the 3rd century, when theDecumatian Fields were cleared,Mogontiacum once again became a border town and was devastated several times over the next 150 years by members of variousGermanic peoples. After the end of the Roman period, but at the latest around 470,Mogontiacum belonged to theFrankish Kingdom after a brief transitional phase.

Some important remains ofMogontiacum have been preserved in the present-day city of Mainz, for example theRoman stage theatre, theGreat Mainz Jupiter Column, theDrusus Stone and theRoman Stones [de], remains of theaqueduct of the legionary camp. TheRoman-Germanic Central Museum, theMainz State Museum and theMuseum of Ancient Seafaring preserve numerous artefacts from Roman rule in Mainz.

The nameMogontiacum is composed of the Celtic nameMogo(n), the Celticsuffix-ontiu- (as in Vesontio/Besançon) and the affiliation suffix*-āko, Latinised to-(i)acum [de].^[1] It thus contains the name of theCeltic godMogon as a component. The name could have been derived from a Celtic settlement of theAresaces, a section of theTreveri people, located in the immediate vicinity of the legionary camp. These were located at the end of the first century BCE in the area of today'sMainz-Weisenau andMainz-Bretzenheim [de].Mogontiacum was first mentioned inhistoriography by the Roman historianTacitus in his workHistories, written at the beginning of the 2nd century, in connection with theRevolt of the Batavi.^[2] The derived spellingMoguntiacum is also common. Abbreviations and different spellings were also common at the time of Roman rule. For example,Moguntiacum was abbreviated toMoguntiaco in theTabula Peutingeriana.Epigraphically, the city name is first documented on a milestone from theClaudian period.

The almost 500-year Roman history ofMogontiacum can be divided into four simplified periods: The first period begins with the founding of the city towards the end of the 1st century BCE and ends with the establishment of the province ofGermaniasuperior and the appointment ofMogontiacum as the provincial capital. The period between 90 CE and 260 CE covers the city's golden age until thefall of theLimes, whenMogontiacum once again became a border town of theRoman Empire. In the third period, from 260 to 350 CE, the city undergoes profound changes in the face of internal turbulence in the Roman Empire and the growing threat from Germanic warriors. The final period from 350 CE to 470 CE reflects the decline of the city, which was plundered and devastated several times during this period.^[3]

In the course ofAugustus' expansionist endeavours starting in 16 BCE, his stepsonNero Claudius Drusus also advanced to the Middle Rhine and secured the area for the Roman Empire. By 13/12 BCE at the latest, possibly earlier,^[4] a double legionary camp was established on a hill above the Rhine and opposite the mouth of the Main. The military presence of the Romans at this location primarily secured their control over the Middle Rhine, the mouth of the Main and generally over the Main as one of the main routes into free Germania.

At the same time, another military camp was built just four kilometres south of today's Mainz district ofWeisenau. This was mainly occupied byauxiliary troops, but was also used temporarily for the stationing of otherlegionaries. This was also the site of one of the lateLatène Celtic settlements in the Mainz area. The local Celtic population belonged to theAresaces, a section of the GallicTreveri, who were located here in their settlement area furthest to the east.^[4]

Until the annexation plans were abandoned in 16 BCE,Mogontiacum served several times as a base for military operations as part of theDrusus campaigns (12 to 8 BCE), the campaign against thekingdom of Marbod (6 CE) and theGermanicus campaigns (14 to 16 CE) inGermania on the eastern side of the Rhine. Shortly afterwards, legionaries inMogontiacum erected acenotaph forDrusus, who died in 9 BCE, in the immediate vicinity of the legionary camp, which is probably identical to theDrusus Stone on theMainz citadel that still exists today. As early as the time of Drusus, a ship bridge was built above the mouth of the Main to cross the Rhine. In the first decade of the 1st century BCE, the bridgeheadCastellum (Castellum Mattiacorum) on the right bank of the Rhine was founded and expanded, which became the nucleus of today'sMainz-Kastel (derived from the Latincastellum). The construction of a fixed wooden bridge (pile bridge) betweenMogontiacum andCastellum can be dated to the year 27.^[3]

After the reorganisation of the Roman Rhine army into an Upper and a Lower Germanic army in the year 17, Mogontiacum became the seat of the commander of the Upper Germanic army. In addition to the rapidly forming camp suburbs (canabae legionis) in the south and south-west of the legionary camp, various civilian settlements (vici) developed, which stretched eastwards down to the Rhine and possibly slowly merged into a coherent settlement structure during the course of the 1st century. In the first half of the 1st century,Mogontiacum already had large civilian buildings with a large publicthermal bath complex and a theatre^[5] mentioned by the Roman writerSuetonius. The Great Column of Jupiter in Mainz, dated to the third quarter of the 1st century,^[6] was donated by an apparently wealthy larger civilian community and can be seen as evidence of the rapid progress ofMogontiacum's civilian development. Despite the beginning development of civilian structures, Mogontiacum remained one of the most important military bases of the Roman army on the Rhine. Two legions, including auxiliaries and tross, were permanently stationed inMogontiacum and in the second military camp in Weisenau, which had been expanded since the reign ofCaligula. Additional troops were stationed as required - for example, after theVarus Battle, when three legions were temporarily stationed inMogontiacum.

During theRevolt of the Batavi, most of the civilian buildings outside the legionary camp were destroyed. According to Tacitus, the camp itself was besieged without success.^[2] Under the rule of theFlavian imperial family, extensive building work was carried out inMogontiacum. The legionary camp was rebuilt in stone underVespasian, and the wooden pile bridge was replaced by a pile bridge with stone piers. During the reign of EmperorDomitian, a stoneaqueduct replaced its wooden predecessor. The aqueduct carried fresh water over a distance of nine kilometres from the springs in today's distant Mainz districts ofFinthen [de] (Fontanetum) andDrais to the legionary camp on the Kästrich.

In 83, the city was the starting point for EmperorDomitian's campaign against the Chatti. To this end, he assembled an army of five legions and auxiliary troops inMogontiacum. In 88 and 89, the governorLucius Antonius Saturninus revolted inMogontiacum. After the rapid suppression, the military territory was transformed into theprovince ofGermania superior withMogontiacum as the provincial capital (caput provinciae), which had already been planned beforehand and was thus finalised.^[3]

The process of transforming the military territory into the province of Germania superior began in the mid-80s of the 1st century and was fully completed by the middle of the year 90 at the latest.^[6] Amilitary diploma^[7] dated 27 October 90 is considered the earliest epigraphic evidence of the newly established province. WithLucius Javolenus Priscus, the province was given aconsular governor who was already experienced as asuffect consul and who quickly developed the necessary civil structures. Beginning under Domitian and continuing under his successors, the Romans secured areas on the right bank of the Rhine to protect the new provinces and consolidate their territory. With the permanent occupation of theNeuwieder Basin [de], theTaunus and theWetterau, theUpper Germanic-Rhaetian Limes was created.^[8]Mogontiacum now assumed the important role of military administrative centre for the Upper Germanic section of the Limes until its downfall.

There were also lasting changes forMogontiacum itself: As a result of the experiences ofSaturninus' revolt, the number of permanently stationed legions was reduced from two to one. From the year 92, this was theLegio XXII Primigenia, which from then on remained the sole legion of Mainz until its defeat in the middle of the 4th century. From 96 to 98, the later EmperorTrajan held the office of governor of the province;Hadrian, his successor, had also been stationed in the province as a military tribune as part of his previous career as amilitary tribune. A time of peace and prosperity dawned forMogontiacum. The border with freeGermania was far advanced and secured by the increasingly elaborate Limes. Trade and crafts flourished in the city and throughout the surrounding area, where manyveterans of the military troops settled. The invasion of the Rhine-Main region by theChatti in 162 and again in 169, as well as the crossing of the Rhine, remained one-off events for the time being without any major impact.^[3]

It would take until 19(?) March 235 for Mogontiacum to once again become the focus of Roman world history. As part of the preparations for a campaign against theAlemanni,Emperor Severus Alexander gathered troops inMogontiacum. There he and his motherJulia Mamaea were murdered by Roman legionaries during riots in or nearMogontiacum in thevicus Britannicus (Bretzenheim [de]?).^[6] This was immediately followed by the proclamation of the military commanderGaius Iulius Verus Maximinus (with the later acquired epithetThrax) as his successor. This was the beginning of the era of thesoldier emperors, which also coincided with the imperialcrisis of the 3rd century.^[9]

Around the year 250 or a little later,^[10] the civilian settlement on the Rhine was surrounded by a city wall. This enclosed the entire previously populated area as well as the largestage theatre, but not the camp canabae to the southwest. This first city wall extended to the fortified legionary camp in the south-west of the city, which supplemented the city wall at this point with its own fortifications. As the so-calledLimesfall is generally dated to the year 259/260, the two events are not directly connected, as previously assumed.^[10] Rather, the presence of Roman troops, who repeatedly had to deploy large detachments for campaigns in distant areas and were distracted by a series of civil wars, was probably no longer considered sufficient to protect the city against raiders. With the abandonment of the Upper Germanic Limes, Mogontiacum once again became a border town - despite further use of areas on the right bank of the Rhine, such as the Castellum bridgehead or the thermal baths in neighbouringAquae Mattiacorum [de] (Wiesbaden).

Almost at the same time as the "Limesfall", there was another significant change in the political situation that directly affected Mogontiacum. AfterMarcus Cassianius Latinius Postumus had succeeded in 260 in uniting parts of the Roman Empire into the so-calledGallic Empire, Mogontiacum also belonged to this state structure until 274. In Mogontiacum, the legateLaelianus proclaimed himself counter-emperor against Postumus in 269. Although Postumus defeated Laelianus in the subsequent civil war and recaptured Mogontiacum, he died immediately afterwards at the hands of his own soldiers, as he did not want to release the city for plundering. From 274, the Gallic special empire no longer existed and Mogontiacum once again belonged to the Roman Empire.

In the course of theDiocletianic reforms and in particular after the reorganisation of the Roman provinces after 297, the province ofGermania superior was absorbed into the (reduced) new province ofGermania prima.Mogontiacum remained the seat of the provincial governor. Somewhat later, the town also functioned as the seat of two military commanders, theDux Germaniae primae [de] and theDux Mogontiacensis, to whom the border army on this section of the Rhine frontier was subject. The first pictorial view of Mogontiacum on the so-calledLyon lead medallion [de] dates from around the year 300. It depicts the walled Mogontiacum, the fixed Rhine bridge and the Castellum bridgehead on the right bank of the Rhine.^[11]

Around 350, the increasingly unstable political situation led to the construction of a second city wall. The military camp and the stage theatre were now located outside the secured city area and both facilities were demolished. In the years that followed, there were repeated incursions by Germanic groups, especially the Alemanni, who were even able to establish themselves temporarily on the left bank of the Rhine. The background to this was probably another civil war in the Roman Empire: in the battles between EmperorConstantius II and the usurperMagnentius, the 22nd legion was almost completely routed in the bloodyBattle of Mursa in 351 and was not re-established afterwards. Themilites Armigeri, possibly a surviving unit of the largely annihilated legion, now took over the protection of the city and the surrounding area. In 368, during a major Christian festival, the city was captured and plundered by the Alemanni under their leaderRando.^[3]

Mogontiacum was not spared the consequences of the so-called "Migration Period" that began around 376. Endless civil wars once again led to a neglect of border defence.^[12] After 400, many regular Roman troops were withdrawn from the Rhine to Italy to take part in the fight against rebelliousVisigothicfoederati. Perhaps in connection with Roman civil wars and probably on New Year's Eve 406,Vandals,Suebi andAlans crossed the Rhine atMogontiacum, presumably using the Rhine bridge, which was probably still intact at the time,^[13] and plundered and destroyed the city (see alsocrossing of the Rhine 406). This led to a temporary collapse of the Roman border defences,^[13] and theRoman Rhine fleet also ceased to exist at this time.^[14]

Around 411,Mogontiacum lay within the sphere of influence of theBurgundian warrior league, with whose support the usurperJovinus was elevated to Roman emperor (possibly inMogontiacum), although he was only able to maintain his position for a short time. The Burgundians themselves were settled as Romanfoederati up the Rhine (centred onWorms/civitas Vangionum [de]) in 413; together with regular Roman units, they monitored the border from then on. However, their sphere of influence was attacked by the Romans as early as 436 and destroyed by Hunnic auxiliaries; the survivors were resettled inSapaudia (roughly modern-daySavoy) in 443.^[15] DuringAttila's invasion ofGaul in 451, the Huns crossed the Rhine atMogontiacum. Although the city was left relatively unscathed, official Roman rule over Mogontiacum ended after this event, or at the latest in the late 460s.^[13][16] Civil Roman structures remained in the partially destroyed city, however, and ecclesiastical representatives of the episcopal see of Mogontiacum possibly took over administrative duties. After theBattle of Tolbiac in 496 at the latest, Mogontiacum was no longer part of the Alemanni's sphere of influence. The city now became part of theFrankish Kingdom underClovis I.

In the historical analysis of the founding and development ofMogontiacum, there is a broad consensus that the founding of the legionary camp in 13 BCE was both the impetus and the nucleus for the later civilian settlement.^[17] Celtic settlements of the LateLatène period, which existed in Mainz-Weisenau and Mainz-Bretzenheim, were of no further significance for the development ofMogontiacum and either emerged at the same time as the beginning of the Roman presence or only existed for a short time.^[18]

The military importance ofMogontiacum continued into the first half of the 5th century. For over 350 years, it was the base of Roman legions and the starting point for campaigns into Magna Germania until the middle of the 3rd century, and to some extent even into the 4th century. For example, Drusus' campaigns, Domitian's Chatti campaign and Severus Alexander's planned campaign against the Alamanni began inMogontiacum. After being proclaimed emperor inMogontiacum in 235, Maximinus Thrax also led his troops far into Germania as part of the Germanic campaign of 235/236 and fought against Germanic troops there (Harzhorn event).^[19]

From the end of the 1st century,Mogontiacum was the administrative and supply centre of theUpper Germanic-Rhaetian Limes. After the fall of the Limes,Mogontiacum was an important border town and the site of a Roman legion and seat of thedux Mogontiacensis until the middle of the 4th century. The military character ofMogontiacum is also reflected in the lack oftown status for the civilian settlement. Nevertheless, it developed relatively quickly from the beginning of the 1st century onwards and over the next few centuries clearly took on a metropolitan character in terms of population, trade and services as well as official buildings.^[3]

The military camp founded by Drusus in 13/12 BCE was one of the two main bases for the planned campaigns into Magna Germania on the right bank of the Rhine. The choice of location, known today asKästrich [de] (derived from the Latincastra), was determined solely by strategic considerations: The Kästrich is a high plateau sloping steeply on three sides, 120 metres above "standard zero" overlooking the banks of the Rhine, which is slightly offset from the point where the Main flows into the Rhine.

The legionary camp was intended to accommodate twoRoman legions (around 12,000 men) from the earlyPrincipate period. Due to the large masses of troops during the campaigns, another military camp was built in Mainz-Weisenau.Auxiliary troops were primarily stationed there, as well as other legionary troops at times.

The legionary camp on the Kästrich was built using a wood and earth technique. It had apolygonal layout and covered an area of around 36 hectares. The camp was already structurally altered inAugustan times and repeatedly in subsequent periods. UnderVespasian, the legionary camp was completely rebuilt in stone. Today, there is archaeological evidence of a total of five different rebuilding and expansion phases. After the withdrawal of the second legion in 89, the 22nd legion remained alone in the legionary camp. Experts are still debating whether the vacated area was used for the construction of the governor's palace and other administrative buildings. With the construction of the second city wall around 350 and the simultaneously decreasing presence of Roman troops inMogontiacum, the legionary camp was abandoned. It was then located outside the city wall ring and was demolished.Spolia of buildings from the camp were found in numerous forms during the demolition of the city wall foundations, especially at the end of the 19th and beginning of the 20th century. The so-called "Mainz Octagon" should be mentioned here as a representative building, which can be at least partially reconstructed thanks to extensivespolia finds that are now stored in the Mainz State Museum. Recent research has attributed it to a gateway similar to thePorta Nigra inTrier. It is possibly the monumentalPorta praetoria facing the Rhine.^[20] The architectural elements can be dated to the last quarter of the 1st century by building inscriptions. The same applies to a large pillared hall with a central passageway, which may have been part of thepraetorium.^[21]

At the beginning of the 20th century, the camp's thermal baths were excavated and documented in the green belt ofMainz's upper town [de]. The course of the wall enclosure is also known, as are the locations of the camp's four gates based on the known course of the roads. During the excavations on the site of today'suniversity clinics [de] (Building 501) in 2003, parts of the camp's internal production facilities (fabrica) with large buildings, fortified access roads and smelting furnaces were excavated and documented. To the south and south-west of the camp were two separate and later merged camp villages (canabae legionis).^[13]

The second military camp in Mainz-Weisenau was also built on a plateau above the Rhine, roughly at the level of today's quarry of theHeidelberg cement works. Based on finds made there, it was mainly occupied by auxiliary troops who belonged to the legions in the main camp. The camp was expanded several times, for example underCaligula when he planned a campaign intoGermania on the right bank of the Rhine in the year 39. In its largest expansion phase, the camp had a total size of twelve hectares. With the withdrawal of the second legion in 89 and due to the changed political situation, a second military camp was no longer needed inMogontiacum and the camp was abandoned. Due to the current situation - the site in question has been used as a quarry since the mid-19th century - there are no longer any traces of the camp.^[13]

Another military camp for auxiliary troops on theHartenberg is suspected, but has not yet been archaeologically verified.^[22]

The Roman troops stationed inMogontiacum can largely be determined from epigraphic remains such as brick stamps,^[23] tombstones (1st century only) or building inscriptions; to a lesser extent, individual Roman troop deployments are also mentioned in historiography, for example inTacitus or in thelate antiqueNotitia dignitatum.

A total of nine different legions were stationed inMogontiacum during the Principate period. Between the years 9 and 17, the troop presence reached its peak with four simultaneously stationed legions and their auxiliaries with an estimated 50,000 soldiers. From the year 93, theLegio XXII Primigenia Pia Fidelis (later with thehonorific names [de]Antoniniana,Severiana andConstantiniana Victrix) was the only legion to occupy the legionary camp until the middle of the 4th century, possibly in parts until the beginning of the 5th century.^[24] TheNotitia dignitatum, which is dated to the first third of the 5th century, mentions themilites Armigerie, presumably a kind of citizenmilitia, for the final period of RomanMogontiacum. They were stationed within the city limits and were under the command of theDux Mogontiacensis or aPraefectus militum armigerorum Mogontiaco.

In addition to the legions, auxiliary troops were also stationed in Mainz. Until the beginning of the 5th century, 13 differentalae and twelvecohorts are attested. From the second half of the 2nd century, an additional four differentnumeri are known for being stationed inMogontiacum.

Shortly after the foundation of the legionary camp and the beginning of the civilian settlement of today's urban area, several harbour facilities were built on the banks of the Rhine. Historical sources and archaeological finds alike prove the great importance ofMogontiacum as a military and civilian port city on the Rhine.^[25]

The first archaeological finds of military port facilities from the mid-19th century were made as part of the expansion of the banks of the Rhine and the development ofMainz's new town. In addition to numerous civilian artefacts, pieces of military equipment were also found at the "Dimesser Ort", near today's customs and inland port. Remains of a solidly built pier made of cast concrete and building remains further down the Rhine, which could possibly be attributed to a Romanburgus, were also found. Similar structures from a later period have been interpreted elsewhere as riverwar harbours. In addition, the river basin protected by a massivemole and aburgus standing further away in the middle of the Rhine on theIngelheimer Aue could be compared to the known main harbour of theRoman Rhine fleet in Cologne-Alteburg as a military harbour area.^[26]

A second Roman military harbour was located upstream on the Rhine at Brand (near Mainz town hall,old town [de]). Due to the structural remains discovered there and theRoman military ships [de] found in 1980/1981, including those of theNavis lusoria type, the identification as a military harbour has been clearly established. Here, too, ship basins separated from the Rhine in several construction phases were localised, which followed the eastward shift of the Rhine bank. The main use of this war harbour was in the second half of the 3rd century and in the 4th century, when the Rhine once again became the border of the province ofGermania superior/Germania prima. Warships patrolled the Rhine fromMogontiacum at this time until the Roman Rhine fleet was disbanded at the beginning of the 5th century following the Germanic invasion of 406/407.^[27]

Even further up the Rhine, the remains of bank defences and ashipyard from the years 5 to 9 were found atNeutorstraße/Dagobertstraße, which was most likely used for military purposes at this time. Inscriptions also name members (signifer/flag bearers) of the 22nd legion as overseers ofnavalia-named ship houses and mention a separatenavalia neighbourhood.^[27]

From its foundation in the 2nd decade BCE until the middle of the 4th century,Mogontiacum was primarily one of the largest and most important military bases on the Rhine. This led to a clear military dominance of the civilian settlements that developed around the legionary camp and the second military camp in Weisenau.^[17][28] Nevertheless, in the 2nd and 3rd centuries, an increasingly urbanised infrastructure developed between the legionary camp and the Rhine bridge as individualvici grew together and, at the latest after the first city wall was built in the middle of the 3rd century, a Roman civilian settlement with a metropolitan character.

Despite the development of urban structures, including large buildings and its function as provincial capital from the year 90,Mogontiacum did not have an official city title such ascolonia,municipium orcivitas. The civilian settlement still had the status of acanabae legionis and was therefore not a city in the legal sense.^[29] It was under thejurisdiction of the legionary legate or governor. The inhabitants ofMogontiacum also referred to themselves ascanabarii in the foundation inscription on the Mainz Jupiter Column. The same apparently also applied to the civilian settlements near the legionary camps inBonn,Strasbourg andRegensburg.^[30]

The first mention ofMogontiacum as acivitas dates back to the years of the firsttetrarchy (after 293 to 305),^[31] at a time when these differentiations in city titles had already been more or less abolished byCaracalla's general grant ofcitizenship (Constitutio Antoniniana in 212).^[32] UnderDiocletian,Mogontiacum is mentioned as ametropolis in the province ofGermania prima.^[33]Ammianus Marcellinus referred toMogontiacum asmunicipium Mogontiacum in 355.^[34]

AfterTiberius renounced the permanent occupation ofMagna Germania with the desiredElbe border, the organisation of the areas on the left bank of the Rhine remained in a provisional administrative stage. The administrative district of the Upper Germanic army (exercitus superior) was merged with the administrative centre ofMogontiacum. The administration, and in particular the financial administration, was subject to the administration of the province ofGallia Belgica.^[35]

UnderDomitian, both a larger and permanent territorial expansion to the right bank of the Rhine (Agri decumates) and the establishment of a new province,Germania superior, took place. It belonged to theimperial provinces and, with an area of 93,500 square kilometres, was one of the medium-sized provinces of the Roman Empire. The existing civilian settlement ofMogontiacum was simultaneously elevated to provincial capital without any change in the legal status of the settlement.^[36] The previous military commander of the Upper Germanic army group (legatus Augusti pro praetore), who was also responsible for civil administration, became the consular governor of the newly founded province, to whom the troops stationed there continued to report as usual.^[37]

When the Roman provinces were reorganised under Diocletian after 297, the much smaller province ofGermania prima emerged fromGermania superior.Mogontiacum remained the seat of the governor, as a mention ofMogontiacum as a metropolis in theNotitia Galliarum shows. The post ofdux Mogontiacensis, newly created during Diocletian's reign as military commander of all troops on the Upper Rhine, also had its seat in Mogontiacum.^[38][39]

At the same time as the legionary camp was established on the Kästrich, twocanabae were built on the neighbouring plateau to the south and southwest of the camp, initially separately. In contrast to the civilian settlement areas, these were semi-military in character. In the Flavian period, as in the civilianvici, thecanabae were extensively developed in stone.^[41] Bothcanabae also grew in the 2nd century and largely merged into one settlement, separated only by the aqueduct at the south-western corner of the camp. When the camp wall was rebuilt in the middle of the 3rd century after the fall of the Limes, thecanabae were also surrounded by a protective wall. When the legionary camp was abandoned a century later and after the destruction of the following years by the Chatti and Alamanni, thecanabae were also abandoned. There is archaeological evidence of cellar pits and a rectangular road system as well as civilian burials in nearby burial grounds.

Shortly afterwards, individual, separatevici developed at the foot of the legionary camp. The earliest archaeological evidence of a civilian settlement dating back to Augustan times can be found directly in front of thePorta praetoria (today'sEmmerich-Josef-Straße [de]). Along the Roman road running from there to the Rhine crossing (today Emmeransstraße), thisvicus slowly expanded in the direction of today's Schillerplatz and the Flachsmarkt. At Flachsmarkt, a second main road coming from the military camp in Weisenau met up with the first-mentioned road. Other civilian settlements established immediately after the beginning of the Roman presence were located in front of the military camp in Weisenau and at Dimesser Ort. The lattervicus is considered the most important civilian settlement and the centre of civilian life inMogontiacum in the first century CE. As a presumed settlement of long-distance merchants, thecanabarii appear to have quickly achieved a certain prosperity, which was linked to the desire for legal recognition of the civil settlement. The foundation of the Great Column of Jupiter in Mainz in the first third of the 1st century has been interpreted in various ways as an attempt by the civilian population to speed up the legal recognition of the settlement.^[42]

With the reconstruction of the destroyed civilian settlement areas after theRevolt of the Batavi and the expansion of the infrastructure in the following period, the individualvici slowly merged into a coherent, urbanised settlement area. In addition, during the time of theFlavian emperors and even more so from the 2nd century onwards, there is evidence of a shift in settlement towards the present-day city centre for the Weisenauvicus and thevicus at Dimesser Ort.^[43][44] The civilian settlement, now centrally located below the legionary camp, extended from the foot of the Kästrich to the Rhine. As there was no coherent building plan, the street network that has been identified to date was not laid out regularly. The central areas of the city centre were probably the Flachsmarkt, where theforum is sometimes assumed to have been located, the Schillerplatz as a flood-protected settlement area and today's cathedral area, where the centralplace of worship is assumed to have been located.

After the construction of the second city wall in the middle of the 4th century, the city area covered 98.5 hectares. A largethermal building in the immediate vicinity of today's State Theatre from the first half of the 1st century is known to have been part of the civilian settlement. A larger administrative building stood in the immediate vicinity of today's municipal retirement home. During construction work in the 1970s, extensive architectural remains, a marble fountain with a bronze fish figure as a waterspout and bricks with the stamps of the Mainz legions were found. The governor's palace is thought to have stood here, which could have been as prestigious as its Cologne counterpart above the banks of the Rhine.^[45] Luxurious city villas were uncovered in the area of Schillerstraße at today'sProviant-Magazin and in the old town (Badergasse), some of which were decorated withmosaics.

There is no record or estimate of the population ofMogontiacum. The somewhat smaller civilianColonia Claudia Ara Agrippinensium had around 30,000 inhabitants around the year 50. Only the size of the stage theatre, which could accommodate around 10,000 spectators, and the general development of the city allow certain conclusions to be drawn about a possible civilian population, which may have been in the lower five-digit range.^[46]

The topography of the civilianMogontiacum is insufficiently archaeologically explored and, compared to other important Roman towns in Germany, has been scarcely researched.^[41] There are various reasons for this. From the earlyMiddle Ages onwards, the high-qualityRoman building materials were continuously reused for the expanding city. There were also repeated instances of deliberate destruction of Roman remains. For example, the stage building at the theatre during the construction of the railway at the end of the 19th century or theMithraeum onBallplatz [de], which was demolished in 1976 despite protests from the population. In general, the Roman settlement area in today's urban area was intensively built over from the Middle Ages onwards.

The aforementioned Dimesser Ort was not only most likely a harbour used for military purposes, but also appears to have been the long-distance trading port of Gallic-Italian merchants.^[47] This is indicated by a high find density of transportamphorae of Mediterranean origin as well as other import finds fromGaul and the Mediterranean region. The structural finds such as stone paving (possibly a loading ramp forflat-bottomed ships) andquays support this assumption. In connection with the trading activities, a prosperous civilian settlement also developed at the Dimesser Ort, which must have been the civilian centre ofMogontiacum as early as the middle of the 1st century.

Other civilian harbours or landing sites with less elaborate quays and cargo houses have also been found upstream on the Rhine near the old town of Mainz (Dagobertstraße, Kappelhof, where two Romanprams from the 1st century were found). The local Celto-Roman Rhine boatmen and traders are likely to have been active here, whose existence is well documented by the tombstone of the shipowner and trader Blussus (dated to around the year 50), for example. Raft shipping was also very important in the Roman period and was probably the most important means of transporting timber on the Rhine toMogontiacum.^[48]

The writerSuetonius mentions^[5] a stage theatre inMogontiacum as early as the year 39. The remains of the theatre visible and uncovered today date from the 2nd century and probably followed an earlier theatre built using wood and earth technology. With a stage length of 41.25 m and a diameter of 116.25 m, it is the largest Roman stage theatre north of the Alps.^[49][50] It could seat over 10,000 spectators. The stage theatre, which stood in the immediate vicinity of the Drusus Stone south of the legionary camp, was most likely used for cult celebrations for Drusus in addition to the regular theatre business, which could explain the relatively large extension.

The theatre was in use until the 4th century, but was located outside the protected city area after the second city wall was built which reduced the size of the city area.Spolia from the theatre area were used for the construction of this second city wall.^[50] The massive cast masonry vault was used as an early Christian burial site from the 6th century onwards. There were still visible ruins of the theatre above ground in the early Middle Ages, which were mentioned in written documents.^[51] The last remains of the theatre visible above ground were levelled in the middle of the 17th century when the citadel was extended.

Shortly after the founding of the camp under Drusus, but at the latest before his campaign fromMogontiacum in 10 BCE, there was probably already afloating bridge (pons navalis) to the right bank of the Rhine. From the year 27 and thus in theTiberian period, the first solid wooden bridge construction isdendrochronologically proven.^[52] This was most probably a pile-yoke bridge. UnderDomitian, a fixed bridge was built at the beginning of the 80s, which crossed the Rhine around 30 metres above today'sTheodor Heuss Bridge. The 420 m long bridge had at least 21 stone piers, 14 of which have been archaeologically proven in the riverbed, each of which rested on elaborately placed pile grids. The wooden bridge superstructure, which supported a 12 m wide multi-lane carriageway, lay on the stone piers. A construction inscription on the bridge ramp on the left bank of the Rhine dates back toLegio XIIII Gemina, which was stationed inMogontiacum between 70 and 92. The Rhine bridge was renewed and repaired several times, for example in the years 100, 157, 213 and in the following decades. It is assumed that it was still or again in use at the beginning of the 5th century and that the Rhine crossing of the Germanic invasion in 406 took place over it. A schematic illustration of the pile-grate bridge can be found on the Lyon lead medallion from around 300.

The bridge had an evenly curved carriageway due to different pier spacing, so that the greatest possible clearance for Rhine ships was available in the centre of the river.^[53] On the right bank of the Rhine, the bridge carriageway led directly into theCastellum Mattiacorum, so the bridge was also militarily secured.

There is also evidence of a smaller bridge over the Main, which was located slightly above the mouth of the Main. There may also have been a second Rhine crossing in the form of a ship's bridge or a permanent ferry crossing. This could have been located below the auxiliary camp in Mainz-Weisenau, but has not yet been clearly verified by research.^[18][54]

To supply the legionary camp on the Kästrich and later also the civilian settlement, an elaborate water pipeline, partly constructed as anaqueduct, was built as early as the 1st century. The water supply to the camp via wells in the inner camp area was not possible due to the groundwater level lying at a depth of over 20 metres.^[55] Transporting water from the neighbouring Zahlbach valley for the camp, which was initially occupied by at least two legions, was also not feasible in the long term.

It is therefore likely that a wooden aqueduct was already in place from the first half of the 1st century, which supplied the camp with fresh water.^[56] The areas of today's Mainz districts of Drais and especially Finthen, which have numerous springs, could be localised as the starting points of this aqueduct. To date, however, there is no reliable evidence of a wooden predecessor building.

As part of the large-scale construction measures of the Flavian emperors, an aqueduct was built in stone, probably at the same time as the expansion of the legionary camp.^[57] The Mainz legionsLegio XIIII Gemina andLegio I Adiutrix were involved in the construction, as shown by brick stamps that allow a relatively precise chronological classification of this building project. The aqueduct ran from the springs in Finthen, initially underground and later in a channel, to the head station at the south-west corner of the camp. The aqueduct was almost nine kilometres long in total. The last three kilometres were constructed as an aqueduct and crossed the Zahlbach valley on arches of over 25 metres, probably two storeys high.^[57] The centre distance was around 8.50 m and the average gradient over the entire length of the pipeline was 0.9 %. Calculations showed a daily water volume of several 100 m³ of fresh water, which was distributed via lead pressurised water pipes in the warehouse and also in thecanabae.

The massive cast wall cores of the pillars can still be seen along a stretch of around 600 metres in the Zahlbach Valley. Some of the pillar stumps, known as "Roman stones", still rise up several metres, but have been almost completely stripped of their former cladding.^[57]

Shortly after the middle of the 3rd century (the section of wall running parallel to the Rhine could be dated to the period 251/253 through the examination of wooden pile grates),^[10] the civilian settlement located between the legionary camp and the Rhine was surrounded by a city wall for the first time. The city wall adjoined the fortifications of the legionary camp to the south-west over a length of 600 metres, although it remained independent. It had rectangular, slightly protruding towers and a moat. It was 2 to 2.50 metres wide and 6 metres high up to the lower edge of the parapet walk. In total, the wall, which was at least 5.1 kilometres long, enclosed around 150 hectares, making it one of the largest city fortifications north of the Alps in Roman times.^[58] The canabae legionis to the south-west of the legionary camp were also fortified, while the civilian settlements at Dimesser Ort and Weisenau lay outside the fortified city area and thus lost further importance. At the same time, the stone wall of the legionary camp was also renewed, now for the third time since the construction of the first stone camp wall under the Flavian emperor.^[59]

AfterJulian's victory over the Alemanni in 357, the construction of a second, shortened city wall was begun in the period 360-370,^[60] probably during his reign. At the same time, the legionary camp was abandoned after more than 350 years and the resulting gap in the fortification was closed by a newly built section of wall in this area. Spolia from the demolished large buildings of the legionary camp were used for this purpose, which were utilised here in large numbers. The demolition of this section of wall between 1899 and 1911 resulted in a large number of high-quality architectural elements, which, among other things, allowed a reasonably reliable reconstruction of the praetorium and other large buildings of the legionary camp and theDativius-Victor Arch.^[61] With the construction of the second city wall, a city area of around 118 hectares was now enclosed, reducing the defences by around a third compared to the phase of the first city wall.^[62]

During construction work on the Kästrich in 1985, remains of the walls of this second city wall, a Roman city gate and the paving of the road leading through it were discovered. The city gate was integrated into the 2.70 metre wide city wall and the via praetoria, which originated from the legionary camp and was a strategically important road leading down to the civilian settlement, passed through it. At a width of 1.90 metres, the ground-in lanes on the gate threshold and the well-preserved sandstone pavement show the typical track width of Roman vehicles.^[63] The city gate was closed with a double-leaf wooden gate and also had a gate tower. The entire gate complex is therefore of the "Andernach" type^[24] and is one of the latest gate complexes known and preserved in Roman Germany.^[64]

The only and most important monument from the time ofMogontiacum still standing at its original location is the so-calledDrususstein. In the meantime, scholars have come to the conclusion that this is likely to be thecenotaph (tumulus honorarius) of the Roman general Drusus.^[65] This was erected by the Roman army inMogontiacum in honour of the general who died of a fatal injury in Germania in 9 BC. The monument was later approved by Augustus, who honoured it with a specially written funeral poem. Roman historians such asSuetonius andEutropius also explicitly mention the Drusus Stone^[66] and the cult ceremonial in memory of Drusus.^[67]

The monument also became the focus of annual cult and commemoration ceremonies (supplicatio) in honour of Drusus, which were attended by delegates from the provincial councils of the three Gallic provinces (concilium Galliarum).^[68] The Roman legions fromMogontiacum honoured their former commander with parades (decursio militum). The nearby theatre with its more than 10,000 seats was probably also involved in these celebrations.^[69]

The remains of the cenotaph that are still visible today are an almost 20-metre-high stone structure made of solid cast masonry with cast stones built into it. The original height was probably 30 metres (equivalent to 100Roman feet). Reconstructions assume a square base and a cylindrical storey (tambour), on which sat a conical top crowned by apine cone [de]. Similar tombs from the early imperial period can also be found on Roman burial roads in Italy.^[65]

TheGreat Jupiter Column of Mainz [de] is a monument erected inMogontiacum in the second half of the 1st century in honour of the Roman godJupiter. It is not only the earliest datable monument of its kind, but also the largest and most elaborate Jupiter column in the German-speaking world. The Mainz Jupiter Column was the model for subsequentJupiter (giant) columns that were erected in the Germanic provinces, particularly in the 2nd and 3rd centuries.^[70] The 9.14 metre high, richly sculpted column was crowned by a 3.36 metre high Jupiter figure with an eagle made of gilded bronze. The surviving donor inscription^[71] is connected with a declaration of loyalty to EmperorNero and identifies thecanabarii, in this case the inhabitants of the civilian settlement of Dimesser Ort on the banks of the Rhine, as the donors. The column, made up of over 2000 individual fragments, is now in the Landesmuseum Mainz, and only a few remains of the bronze figure have survived. A faithful replica of the Great Mainz Jupiter Column now stands in front of theRhineland-Palatinate State Parliament in Mainz.

Another important monument from the middle of the 3rd century is theArch of Dativius Victor. In RomanMogontiacum, this arch served as the centre passage of a portico of a public building, possibly near the legionary camp. A large part of the arch (43 of a total of 75 individual sandstone blocks) was discovered asspolia between 1898 and 1911 during the demolition of the medieval city wall in the lower, late Roman foundation area. This arch is also decorated with lavish reliefs, including a partially preservedzodiac, vines and Jupiter/Juno. The fully preserved inscription^[72] names Dativius Victor,decurio of thecivitas Taunensium (councillor of the Taunensian local authority in Nida) as the founder. He may have settled inMogontiacum as a result of the increasing unrest caused by the Alemanni invasions that began in 233 and donated the arch out of gratitude. Like the Mainz Jupiter Column, the original is located in the stone hall of the Mainz State Museum, while a replica can be found in the immediate vicinity of theElectoral Palace and the Roman-Germanic Central Museum.

In 1986, the foundations of a large three-tower structure were found in Mainz-Kastel, which may have been an arch of honour. It is possible that these are the remains of the arch of honour forGermanicus, the son of Drusus, mentioned in Tacitus,^[73] theTabula Siarensis^[74] and theTabula Hebana [de].^[75] Mention is made of the erection of three arches of honour for Germanicus after his death in the year 19, one of which stood inMogontiacum apud ripam Rheni. However, the chronological and personal attribution of the foundations found is disputed. The presumed arch of honour could also have been erected byDomitian during his Chatti Wars.^[76][77]

Mogontiacum was the centre of religious and cultic life in the surrounding area. Due to the character of the city, this was a clearly militarised practice. The imperial cult in the complex around the Drusus Stone, starting with the cult and commemorative celebrations in honour of Drusus and his son Germanicus, played a major and central role in the early days ofMogontiacum.^[78] Later, the religious and cultic life appropriate to a provincial capital developed, which also spread to the surrounding area. On the part of the Celtic-Roman population, the worship of local, relatively quickly Romanised Celtic deities flowed in.

Nine cult sites from Mainz and the surrounding area have so far been archaeologically discovered or can be assumed on the basis of archaeological evidence. A further nine cult sites are only attested epigraphically.^[79] On the other hand,Mogontiacum has the largest number of consecration monuments of the Gallic and Germanic provinces, including 272 consecration inscriptions alone. However, the majority of these were found as spolia from the wall base of the late antique-medieval city wall and therefore do not allow any conclusions to be drawn about the geographical location of the sanctuaries. Cult sites ofJupiter,Juno andMinerva and perhaps alsoApollo may have been located in the area of today's cathedral district, but there is no direct archaeological evidence for this.^[80] WhetherMogontiacum, like Trier or Cologne, had a sanctuary of the "Capitoline Triad" is questionable due to the lack of an official city character. Numerous dedication stones, exclusively from legionarylegates, point to a sanctuary of Apollo and another unknown deity in the 3rd century in the immediate vicinity of the Rhine bridge.^[81] Epigraphically confirmed are a sanctuary ofBellona in Castellum and asacellum ofMercury between Mainz and Mainz-Hechtsheim. Sanctuaries of theGenius Loci,Bonus Eventus andFortuna Conservatrix have also only been identified epigraphically, but could not be localised.^[82]

A more precise localisation is possible for other sanctuaries and cult sites. As early as 1976, aMithraeum was excavated at theBallplatz [de] and thus at the foot of the Kästrich with its legionary camp, but it was destroyed in the course of further construction work.^[83][84] What is unusual here is the very early worship of Mithras, which was dated by pottery finds to the period between 70 and 80 and thus to the Flavian period. With a total length of 30 metres, it is the oldest and largest known Mithraeum in the Roman Empire. The date of construction, size and furnishings indicate that the sanctuary was held in high esteem and played a major role in the spread of the cult in the two Germanic provinces.^[85]

The jointcult complex of Isis and Mater Magna, however, which was discovered in 1999, was excavated under archaeological supervision, conserved and presented to visitors as a museum together with some of the rich finds from religious and cultic life. As with theMithraeum, the early dating of the sanctuary to the Flavian period, or more precisely to the time of Vespasian, is surprising. Until the discovery, it was not known that the cult of Isis had penetrated the northern provinces of the Roman Empire so early. Scholars assume that the reason for the early establishment of this oriental cult (as well as the above-mentioned cult of Mithras) was the massive military presence inMogontiacum.^[86]

The many individual finds provide detailed information about the official cult practices in honour ofIsis andMater Magna inMogontiacum. Other outstanding epigraphic evidence includes the large number of leadcurse tablets found, which, together with the magic dolls found, provide an insight into the magical-ritual cult world of the simple provincial Romans, which was forbidden under Roman law and practised illegally.^[84]

The sanctuaries of Mercury andRosmerta inFinthen [de] and MarsLeucetius andNemetona inKlein-Winternheim, which were found outside the settlement area at the time, are not located directly inMogontiacum, but are clearly more closely related to the settlement and military camp. The first pair of gods is thought to be a larger temple modelled on the Gallic temple from around the year 100. The life-size bronze head of a goddess found there in 1844 is generally thought to be an effigy of the Celtic goddess Rosmerta. She was often worshipped together with the Roman god Mercury or his Celtic pedant. The high-quality bronze dates to the beginning of the 2nd century and shows clear influences of the Roman style, but was probably made locally in Mainz.^[87]

The smaller sanctuary of Mars Leucetius and Nemetona was located even further outside the core settlement area and, like the sanctuary of Mercury/Rosmerta, probably dates back to an Aresacian sanctuary from pre-Roman times. A bronze votive tablet^[88] by the senator Fabricius Veiento and his wife for Nemetona from the Flavian period proves that the Celtic goddess was also worshipped in Flavian times.

In 2020, archaeologists excavating in the area of the customs harbour found a life-size, elaborately crafted but headless statue of a female figure with her foot resting on a calf's head. This 1.49 metre high figure was later identified asSalus, goddess of well-being and salvation.^[89] The cult of Salus was established in the second half of the 1st century and is associated with the period of prosperity that began in the Roman provinces on the Rhine at this time. The founders and the year of the foundation are known from the inscription on the plinth. Senecianus Moderatus and Respectus Constans^[90] were residents of the "Dimesser Ort" civilian settlement near the customs harbour and donated the statue in 231. In addition to its hoped-for healing effect for the emperor and the state, the foundation and the erection of the statue in a public space also increased the prestige of the donors and their civilian settlement.^[91]

The economic importance ofMogontiacum as a trading centre and production site increased rapidly after the foundation of the legionary camp. Finds from the campcanabae and the civilianvici indicate a steadily growing economicprosperity, especially from the Flavian period until the abandonment of the Limes.^[43]

In view of the number of soldiers stationed there, at times up to four legions including auxiliary troops, it can be assumed thatMogontiacum quickly became an important centre for local and long-distance trade. The location on the Middle Rhine and inland waterway transport probably also played an important role in local transport, as evidenced by finds of cargo and transport barges or the tomb of the wealthy Romano-Celtic bargeman Blussus in Mainz. The subsequently flourishing civilian settlements, in particular the civilian settlement at the "Dimesser Ort" with its Gallic-Italian long-distance merchants,^[42] also benefited from trade and the transhipment of goods via Rhine navigation.

Trade flows from the surrounding countryside now also converged inMogontiacum. Well-developed roads led fromMogontiacum to Cologne, Trier, Worms and beyond viaAlzey to Gaul. With the construction of the fixed Rhine bridge during the Flavian period, trade and the exchange of goods with settlement areas on the right bank of the Rhine also increased significantly.^[92] With the increasing settlement of military veterans in the urban area or in the surrounding area ofMogontiacum (villae rusticae have been found in all Mainz suburbs), the number of craft and agricultural businesses supplying the military and civilian population also increased.^[93] In the individualvici ofMogontiacum, entire craftsmen's quarters developed, such as a significant collection of shoemakers' workshops along the camp road down to the Rhine in the area of today's Emmeransstraße. There were also pottery workshops (for example in the area of today's government quarter), metal workshops orbone and leather processing businesses at the northern end of the settlement area as well as armouries for the soldiers stationed inMogontiacum.^[94]

In the first decades after the foundation of the legionary camp, inland shipping, which was in the hands of the Celtic population, flourished in the civilian settlement near Weisenau. This was then increasingly superseded by a large number ofpottery businesses and a veritable "pottery industry" from the Flavian period onwards, which became the main source of income for the local civilian population.^[93][95] There was also a Roman lamp factory there, dated between the years 20 and 69, which may have been a military operation.^[42]

A larger thermal bath building was built in the year 33 in the immediate vicinity of today's State Theatre and thus at the fork in the main road coming from the legionary camp. Due to thesilty subsoil at the time, the building was placed on a pile foundation, the remains of which made it possible to date it precisely. The baths must have been one of the first large stone buildings in the otherwise sparsely populated city centre area. It was already destroyed in the second third of the 1st century, possibly in connection with the destruction of civilian facilities inMogontiacum during the Batavi War.^[96] A successor building possibly stood somewhat offset and more central to the inner city centre that developed from the Flavian period onwards at today's Flachsmarkt. During construction work in the 1980s, massive remains of a larger building complex from the late 1st century were found 200 metres away inHintere Christofsgasse. Large quantities of stampedhypocaust bricks and parts of a marble fountain could possibly speak in favour of a thermal bath building.

The fort baths belonging to the legionary camp were the only major building complex in the camp to be excavated and mapped in 1908. The fort baths were relatively large at 69 × 50 metres and were probably only built after the withdrawal of the second legion stationed inMogontiacum after the year 90. Based on the structural remains, two construction phases could be determined:^[97] an older and smaller bath complex with a circular rudatorium from the late Flavian or early Trajanic period and a larger, completely remodelled second bath complex from the early Hadrianic period. This bath was in use until the camp was abandoned in the middle of the 4th century, as evidenced by a stamp of the 22nd legion with the addition C.V. forConstantiniana Victrix. The legion only used this name suffix from Constantinian times.

There were numerous cemeteries inMogontiacum, which spanned the settlement area in an arc.^[98] They were created in the 1st century and were used continuously until the 4th century, in some cases until the early Middle Ages.^[99] The starting points for the cemeteries were usually the transport routes leading from the legionary camp. In addition to the numerous smaller cemeteries aroundMogontiacum, two larger burial sites can be identified, in Oberstadt/Weisenau and in Bretzenheim on the slope of the Zahlbach valley below the camp. Most of the gravestones found in Mainz to date also come from these two cemeteries.

A cemetery road (via sepulcrum)^[100] modelled on the Italo-Roman road existed along the connecting road between the legionary camp and the military camp orvicus in Weisenau. Evidence of Roman burial sites has been documented there since the end of the 18th century. After an initial investigation by Ernst Neeb in 1912, the burial sites there were only systematically researched between 1982 and 1992. Beginning with the starting point of the road at the legionary camp and in the vicinity of the Drusus Cenotaph, burials along the road have already been documented for the Augustan period. One of the first burial monuments in the immediate vicinity of the camp, which was created at the same time as the Drusus cenotaph, is the high-grade burial monument of the brothers Marcus and Caius Cassius, originally fromMilan and members ofLegio XIIII Gemina, which is known as the "Cassian Monument". In the direction of Weisenau, more and more burial monuments and grave enclosures were erected to both sides of the road, separated from it by a ditch, over a length of 2.5 kilometres until well into the 4th century. Due to its prestigious character along the important military road and its initial proximity to the Drusus Cenotaph, this burial site was evidently favoured by military personnel, Roman citizens living there and the wealthy Roman upper class.^[101] The military and civilian burials were carried out partly according to Italic custom and partly according to local customs. From the 2nd century onwards, the representative significance of the cemetery road slowly declined; some of the stone structures were demolished, and the material reused to build new tombs.Burial monuments were also removed as building material for the construction of the city wall in the 3rd and 4th centuries and incorporated in the form ofspolia. Other cemeteries, especially in the northern settlement area, now became increasingly important.

A large Augustan military cemetery was located on the western slope of the Zahlbach valley, below the legionary camp. Numerous military burials took place here in the 1st century. The majority of the military gravestones found in Mainz, many of which are of high quality and epigraphic value, come from this cemetery. In the course of the 1st century, the cemetery expanded further southwards across the plateau. Towards the end of the 1st century, the number of military burials decreased drastically and shifted southwards near the theatre. The cemetery was now increasingly used by the civilian population of the increasingly important camp canabae, in the direction of which it expanded during the 2nd and 3rd centuries. A burial tradition could be established until well into the 4th century. The abandonment of this burial ground is certainly directly related to the abandonment of the legionary camp and the campcanabae around the middle of the 4th century.^[99]

Numerous other smaller cemeteries existed, for example, in today'sNeustadt at Dimesser Ort or in the Gartenfeld, on the grounds ofMainz's main cemetery and theJohannes Gutenberg University and in almost all other suburbs of Mainz. Cemetery churches were built near some of these burial grounds in the late Roman period, which went hand in hand with the increased number of Christian burials up to the Frankish period.^[99]

In contrast to other larger Roman cities such as Trier or Cologne, the topography of Mogontiacum still has major gaps. It is therefore not surprising that the location of some of the larger administrative and civil buildings and squares is still unknown. The governor's palace built after the establishment of the province of Germania superior from the mid-80s of the 1st century is one of the large buildings that have not yet been localised. Several possible locations have been considered and discussed among experts. As the legionary camp was only occupied by one legion after the withdrawal of Legio XXI Rapax in the year 90 and offered enough space, the construction of a governor's palace and other administrative buildings in the inner area of the legionary camp was considered. Agraffito on a shard of clay from the 2nd century gives the governor's address as "... praetorium ... ad hiberna leg XXII P P F" and is regarded as evidence in favour of this hypothesis.^[96] Recently, however, there has been a tendency to look for the location of the governor's palace outside the legionary camp, despite this inscription.^[102] Larger building remains with stamped bricks and marble furnishings in the old city centre in the area ofHintere Christofsgasse/Birnbaumgasse could be the remains of the sought-after governor's palace, which, similar to its Cologne counterpart, could have stood above the banks of the Rhine and elevated above it. It would also have been close to the "Flachsmarkt", the centre of the growing civilian settlement^[103] that emerged from the Flavian period onwards. Future excavations planned in the area of Birnbaumgasse should contribute to further clarification here. Another possible location would have been the area near today'sState Theatre, which was also considered the central square in the area of the civilian settlement.

According to some scholars, theforum ofMogontiacum is most likely to have been located in the area of today'sSchillerplatz [de].^[92] The central and flood-free location in the immediate vicinity of the legionary camp is an indication of this localisation. At the same time, Schillerplatz is the centre of numerous Roman roads that converged on it, giving the square a certain traffic centrality. Other possible locations, similar to the governor's palace, are the areas of Flachsmarkt and the urban area where the Mainz State Theatre complex and its annexes stand today.

In addition to theRoman stage theatre, there was almost certainly also anamphitheatre inMogontiacum. Dedications bygladiators found on site are evidence of its existence. However, there are only vague indications as to its location. One possible location would be the Zahlbach valley near the Dalheim monastery, now no longer in existence, which would also be supported by its proximity to the legionary camp.^[104] In the records of the Mainz monk Siegehard from around 1100, there is mention of the ruins of a theatre in the Zahlbach valley, which is said to have been built for gladiator and circus games.^[105] In hisOld History of Mainz (several volumes, published from 1771), Father Joseph Fuchs located the Mainz amphitheatre in a different place, namely between today's city centre and theHechtsheimer Berg. There was a large semi-circle there, at the bottom of which the remains of strong pillars had been found.^[106]

The temple district for the state deities Jupiter, Juno and Minerva (Capitoline Triad) is also unknown. Based on the discovery of dedicatory inscriptions, the cathedral district is the most likely location; however, this hypothesis is not archaeologically verifiable.^[3]

In addition to the civil settlements in Weisenau and Bretzenheim, numerous villae rusticae developed over time in the immediate vicinity ofMogontiacum. There is evidence of these for example inGonsenheim,Laubenheim, between theLerchenberg andOber-Olm and in almost all other suburbs of Mainz. They were increasingly responsible for supplyingMogontiacum with food and other agricultural goods, with the result that the civilian settlement gradually assumed the central market function for the surrounding area.^[93][107]

The nearest larger settlements on the left bank of the Rhine wereBingium [de] (Bingen),Altiaia [de] (Alzey) and above all theCivitas Vangionum [de]/Borbetomagus [de] (Worms). Other larger cities such asAugusta Treverorum (Trier) or theColonia Claudia Ara Agrippinensium (Cologne) were also quickly accessible via well-developed roads such as the Roman road that preceded today'sHunsrückhöhenstraße [de] or theRheintalstraße [de]. On the right bank of the Rhine,Aquae Mattiacorum [de] (Wiesbaden) was founded in the late 1st century as the nearest neighbouring town. The hot springs there were highly valued by the Romans and remained in Roman hands until the middle of the 4th century.^[108]

In the Gonsbach valley, which is part of theGonsenheim district of Mainz, surprisingly large ruin complexes and the high-quality relief of a bound Teuton were found at the end of 2013 during "renaturalisation" measures. The size and structural quality of the Roman remains suggest that they were used for military purposes. A larger circular structure with a diameter of 40 m resembles anoval track or alungeing course in modernequestrian sport, so that this was possibly a facility for Romancavalrymen and their training - also in view of the favourable location of the stream andmeadows for keeping animals. The site has since been identified by the responsible archaeologists from theMainz Archaeology Directorate, Marion Witteyer, as astud farm from late antiquity, which was possibly operated by the military stationed inMogontiacum.^[109]

Over the centuries, many finds from the time of the ancientMogontiacum have certainly been made in Mainz. In the early and highMiddle Ages there were virtually no records of this in historiography, but this changed with theRenaissance and the subsequentAge of Enlightenment at the latest. At that time, significant individual finds were mainly stone artefacts such as gravestones or monuments. There was then a significant increase in individual finds, especially in the 19th and early 20th centuries, when intensive building activity began in the town and older structures such as the Roman-medieval town wall were finally demolished. Other small finds were repeatedly made in theRhine, such as the "Sword of Tiberius" in 1848. This is a very well-preservedgladius with richly decorated brass fittings on thescabbard. These show high-quality motifs from the official political and propagandistic image programme ofTiberius' Germanic policy.^[110] Both have been in theBritish Museum in London since the 19th century, a copy of which can be found in the Roman-Germanic Central Museum. In the second half of the 20th century, a number of individual finds were made, which today are among the most important artefacts fromMogontiacum's Roman past. In 1962, the year of the supposed 2000th anniversary of the city of Mainz, a marble head was found that dates back to the early 1st century. The person depicted is attributed to theJulio-Claudian imperial family and was made in an Italian workshop. No qualitatively comparable counterpart has yet been found in Mainz. As the find was made by chance without any direct context, the authenticity of the piece was initially doubted. In the meantime, however, the dating of the marble head has been confirmed by detailed analyses.

In 1981, a total of nine different ship remains from the early and late Roman period were found in an excavation pit near the Rhine. TheMainz Roman ships [de] were the more or less well-preserved remains of a total of five military ships of two different types (Navis lusoria) as well as civilian cargo ships such as a barge. The special significance of the finds not only resulted in extensive restoration work, but also led to the establishment of a dedicated research centre for "Ancient Seafaring" in Mainz and the establishment of its own museum.^[111]

In 1999, the architectural remains of an Isis and Mater Magna sanctuary from the 1st century were unexpectedly discovered. The finds provide a detailed insight into the cultic-religious everyday life of the provincial Roman population ofMogontiacum. Of particular importance are the 34 differentcurse tablets found here, which almost double the number of curse tablets known in Germany.^[111]

It is not clear whenchristianity first gained a foothold inMogontiacum. The current state of research is that there is no definitive evidence of any kind of organised christianity or christianmartyrs inMogontiacum in the period before theConstantinian shift.^[112] Even after the Constantinian shift in the religious policy of the Roman Empire, the development of an organised church community was slow. Due to the city's centuries-long status as a central military base, other religious cults such as theimperial cult and other cults favoured by the military, such as the worship of Mithras, continued to dominate for a long time. Compared to other, less militarised cities such as Trier or Cologne, this delayed the development of a christian community inMogontiacum.^[113]

The first confirmed reference to a larger christian community inMogontiacum dates back to 368. In connection with the invasion of the Alemanni underRando,Ammianus Marcellinus reported on a large number of christians who gathered for a church festival^[114] and were partly abducted by theAlemanni.^[115] Ammianus explicitly emphasises that the captives included men and women of all social classes, which suggests that a christian community with believers from the upper classes had already been established for some time.^[116] A second indication of a large church community inMogontiacum is provided by thelate antique church father and theologianJerome in a letter written to the Gallo-Roman Ageruchia around 409:

"Mogontiacus, once a highly famous city, was conquered and lies destroyed, many thousands were slaughtered in the church ..."^[117]

Jerome refers here to the destruction ofMogontiacum (incorrectly speltMogontiacus) during the crossing of the Rhine by Germanic peoples in 406/407. Themartyrdom ofSaint Alban of Mainz, which he suffered inMogontiacum, is also associated with this event. Two other Christian martyrs are possibly attributed toHun invasions that took place around 436 in connection with the destruction of theBurgundian Empire on the Rhine^[118] or later to Hun soldiers duringAttila's western campaign in 451. The bishop ofMogontiacumAureus and his sister Justina are said to have been martyred in the process.

In older literature, the first bishop ofMogontiacum known by name is a Mar(t)inus. The signature of a Martinus episcopus Mogontiacensium at a synod in Cologne on 12 May 346, at which 14 Gallic and Germanic bishops met to depose and excommunicate the bishop of Cologne,Euphrates [de], is regarded as proof of this. It is now generally accepted that the records of this synod date back to a forgery, probably from the 10th century, and that this synod, at least with this aim, did not exist. Moreover, a Bishop Mar(t)inus cannot be fixed historically apart from his mention there.^[119]

This also applies to a number of other bishop names from Roman times, which are mentioned in eight different versions of medieval bishop lists. Beginning with a Crescentius in the 1st century, who was regarded as a pupil ofPaul of Tarsus, a varying number of bishops are named up toSidonius [de], who can be traced back to the middle of the 6th century. Only Aureus is considered relatively certain for the middle of the 5th century. It is possible that there were Roman bishops with the names Marinus, Theomastus/Theonest, Sophronius/Suffronius or Maximus before this, but these are not historically clear, but at best can only be identified indirectly.^[120][121] One indication of the earlier existence of Roman bishops in Mogontiacum is the reference in the greeting by the church scholarHilary of Poitiers from the year 358/359, which he dedicates to the "beloved and blessed brothers and fellow bishops of the provinces of Germania prima and Germania secunda", among others.^[122]

The location of an official Roman episcopal church and its date of origin are still unclear and are the subject of controversial debate among experts. What is relatively certain is that this church could not have been located under today's cathedral site. Excavations in 1950/51 (and 2013 to 2017) uncovered the foundations of a larger late Roman building under the nearby Protestantchurch of Saint John. Since then, these have often been interpreted as the remains of the first episcopal church, which can be thought of as afamily of churches [de] with a cathedral.^[13][123] The period after 350 and before 368 (mention of a larger christian community by Ammianus Marcellinus) is now regarded as the possible date of origin of an episcopal or at least larger church.^[124]

The only late Roman sacred building inMogontiacum that was clearly proven archaeologically in 1907/10 was thebasilica of Saint Alban. This cemetery church in the area of the burial ground to the south was built in the first half of the 5th century using high-quality Roman masonry. The dedication to thepatron saint Alban of Mainz suggests that it was built shortly after the Germanic invasion in 406/407. His martyrdom probably took place in connection with the devastation of the city.^[125][126] It is possible that there was already a predecessor building in Roman times, as indicated by Christian gravestones from the late 4th century found on site. The single-nave basilica without apses was built over the tomb of Saint Alban and measured 15 × 30 metres.

The emergence of further cemetery churches in the late 4th and early 5th centuries can only be indirectly attributed to the Roman period, but is considered probable.^[127] The chapel and later church ofSaint Hilary was the burial church of the bishops of Mainz until the 8th century, which speaks for its early importance. It was built in the Zahlbach valley, from the early 1st century the burial place mainly of the military and, in early Christian tradition, the vallis sacra of Mogontiacum. Further to the north, Saint Theomast (which gave its name to the village of Dimesser Ort), Saint Clemens and Saint Peter (Saint Peterex muros or Old Saint Peter) can also be assumed to have been built in late Roman times. In the case of the latter church, this is relatively certain due to the continuity of gravestones with Roman and Germanic names.^[123]

Research into the Roman Mogontiacum began in electoral Mainz in the age of theRenaissance and under the influence ofhumanism. Again and again, scientists, scholars, but also clergymen, military officers and civil engineers from the electoral court or theUniversity of Mainz were involved. A pioneer of research intoMogontiacum wasDietrich Gresemund,doctor of both laws andcanon ofSt. Stephan's. He collected Roman inscriptions and wrote a treatise on his collection as early as 1511, which was lost after his sudden death in 1512. He was directly followed by Johannes Huttich, who published his workCollectana antiquitatum in urbe atque agro Moguntino repertarum in 1520 with the support of ElectorAlbert of Brandenburg. Other researchers of Roman history included the Mainz cathedralvicar Georg Helwich, whose workAntiquitates Moguntiacenses has been lost, as well as writings by Heinrich Engels, dean of St. Peter's Abbey, and Johann Kraft Hiegell, military physician to the Elector of Mainz. The commander of theMainz fortress, Johann Freiherr von Thüngen, also joined the circle of collectors of Roman monuments and book authors. Due to the intensive building activity in Mainz after theThirty Years' War, especially during the expansion of the Mainz fortress, many Roman stone monuments were found, which Thüngen was able to examine and describe at first hand.^[128] This work has also been lost.

The second half of the 18th century was an important period in the history of research into Mainz's Roman past. In 1765, the Elector of MainzEmmerich Joseph von Breidbach zu Bürresheim gave all the Roman stone monuments that had been found and collected to date to ElectorKarl-Theodor von der Pfalz. After drastically decimating the stock of Roman stone monuments in this way (some of these pieces can still be found today in theReiss-Engelhorn-Museums of the city ofMannheim), he commissioned theBenedictine priest Joseph Fuchs to write a comprehensive work on the history of Mainz in return. Father Fuchs' work on the ancient history of Mainz was generously sponsored by him and the first two volumes were published in 1771/72. Further volumes were planned, and some manuscripts already existed, but the death of his patron in 1774 interrupted Fuchs' work. Nevertheless, the two published volumes with their numerous copperplate engravings of Roman inscriptions and monuments and Fuchs' work in general are considered a significant breakthrough in the research and documentation of Mainz's Roman past. In the last quarter of the 18th century, the public exhibition of collected Roman stone monuments also began. In 1784, under ElectorFriedrich Karl Joseph von Erthal, the first Electorate of Mainz law on the preservation of monuments was passed and a cabinet of coins and antiquities attached to the University of Mainz was founded.^[129]

During the years when Mainz belonged to theFrench Empire (1792/93 and 1798 to 1814), it was above all the librarian and university professor Friedrich Lehne who took a greater interest in Mayence's Roman past. His commitment was favoured by the French administration, which set up aCommission pour la conservation des antiques as early as 1798 and planned an "antiquities museum" in the form of theConservatoire des antiques à Mayence. The Roman past also played a major role in theSociété départementale, founded in 1802, of which Lehne was secretary. Lehne gave numerous lectures on Roman history and wrote treatises on the same subject, for example on the Eichelstein. With the support of the French prefectJeanbon Saint-André, he carried out the first systematic excavations in Mainz. He uncovered a large number of military gravestones at the former military cemetery on the slope of the Zahlbach valley. With these and older artefacts, he set up a publicly accessible antiquities hall in the former Burse on Neubrunnenplatz. Its collection of Roman stone monuments quickly grew in importance and also attracted famous guests such asJohann Wolfgang von Goethe, who wrote about it several times. This collection was later transferred to the Mainz Museum of Antiquities (now theMainz State Museum) and is now on display in the so-called Stone Hall, the formerriding hall of theElectoral Stables.^[129]

Until the middle of the 19th century, local notables such as Karl Anton Schaab (Electoral-Mainz court advocate and later vice president of the district court), Nikolaus Müller (painter, writer and curator of the picture gallery) and Ludwig Lindenschmit the Younger (artist, later director of the Roman-Germanic Central Museum) were the driving forces behind research into the Roman past of Mayence/Mainz. In 1841, theGesellschaft der Freunde vaterländischer Geschichtsforschung und Altertumskunde was founded in Mainz, followed by theRömisch-Germanisches Zentralmuseum in 1852. For the first time, this ensured the scientific processing, evaluation and preservation of Roman artefacts. In 1875, J. Becker published his workDie römischen Inschriften und Steindenkmäler des Museums der Stadt Mainz (The Roman Inscriptions and Stone Monuments of the Museum of the City of Mainz), which was supplemented and expanded a total of four times up to the beginning of the 20th century. Between 1904 and 1907, all known Roman inscriptions were published in theCorpus Inscriptionum Latinarum (Volume XIII). Since the 1980s, research into Mainz's Roman past has been in the hands of the state of Rhineland-Palatinate, which provides archaeological support via the Mainz branch of the Rhineland-Palatinate Directorate of State Archaeology (part of theRhineland-Palatinate General Directorate for Cultural Heritage, GDKE).^[129]

Founded in 1803, today'sLandesmuseum Mainz has housed an important collection of Roman stone monuments from Mogontiacum since its foundation. This consists of around 2000 individual pieces, of which just over 1000 are completely preserved. It includes civil and military funerary monuments, altars, inscriptions, architectural elements and well-known individual finds such as the large Mainz Jupiter Column, the Dativius Victor Arch, the bronze head of a Celtic goddess ("Rosmerta") and the "Mainz Marble Head". After more than 200 years, the collection was spun off in 2010 and assigned to theRoman-Germanic Central Museum (RGZM), which will display it in its new building atMainz Roman Theatre station from 2024.^[130] The museum also has an extensive Roman period collection consisting of pottery, glassware, military equipment, jewellery and other small finds.

The RGZM was founded in 1852 as a result of the activities ofLudwig Lindenschmit the Elder and other members of theMainz Antiquities Society [de] and is currently still located in theElectoral Palace in Mainz. However, a move to new buildings at Mainz South Station is planned. In addition to various other thematic departments, the RGZM has a department dedicated toprovincial Roman archaeology [de], where it also exhibits finds made mainly in Mainz. The RGZM issues its own publications in the form of theArchäologisches Korrespondenzblatt [de], the RGZM Yearbooks and other specialist monographs.

The museum also includes the world-renowned restoration workshops of the RGZM and theMuseum of Ancient Seafaring with the research area of Ancient Seafaring. This research area was established after the salvage and restoration of theMainz Roman ships [de]. The museum was subsequently founded and has been housed at MainzSüdbahnhof (nowMainz Roman Theatre station) since 1994. In addition to other exhibits on the subject, the restored Roman ships from the 1981/82 ship finds and the full-size replica of two warships are on display here.^[130]

In the basement of theRömerpassage inMainz city centre [de], numerous small finds that came to light during the excavations are exhibited together with the structural remains of theIsis and Mater Magna sanctuary found there. A number of smaller local museums are also dedicated to the Roman past, such as the Museum Castellum inMainz-Kastel and smaller local exhibitions in banks, ministries and other public buildings in Mainz.^[130]

• Mainz in Roman times (in German).
• General Directorate of Cultural Heritage - Directorate of Archaeology Mainz (in German).
• Theatrum Mogontiacensium (in German).
• Virtual reconstruction of Mogontiacum.
• "Mogontiacum (Mainz) - Livius".livius.org.

• Settlements in Germania Magna
• Roman sites in Germany
• Germania (Roman province)
• Roman towns and cities in Germania
• Roman fortifications
• Celtic toponyms
• Gallic Empire
• Roman legionary fortresses in Germany

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