Leo III the Isaurian (Greek:Λέων ὁ Ἴσαυρος,romanized: Leōn ho Isauros;c. 685 – 18 June 741), also known asthe Syrian, was the firstByzantine emperor of theIsaurian dynasty from 717 until his death in 741.^[1] He put an end to theTwenty Years' Anarchy, a period of great instability in the Byzantine Empire between 695 and 717, marked by the rapid succession of several emperors to the throne, along with ending the continual defeats and territorial losses the Byzantines had suffered during the 7th century. He also successfully defended the Empire against the invadingUmayyads andforbade the veneration of icons.^[2]

Leo III the Isaurian
Emperor of the Romans
Solidus of Leo III markedleonpa mul.
Byzantine emperor
Reign	25 March 717 – 18 June 741
Predecessor	Theodosius III
Successor	Constantine V
Born	Konon c. 685 Germanikeia,Umayyad Caliphate (nowMarash,Turkey)
Died	June 18, 741(741-06-18) (aged 55–56)
Spouse	Maria
Issue	Constantine V Anna Irene Kosmo
Regnal name Leo
Dynasty	Isaurian dynasty
Religion	Chalcedonian Christianity

Leo III was born inGermanikeia,Commagene, which is in modernKahramanmaraş inTurkey. His original name wasKonon (Greek:Κόνων).^[3] Leo III was fluent in Arabic,^[4] possibly as a native language,^[5] and was described byTheophanes the Confessor as "theSaracen-minded," although there is very little evidence that he was directly influenced byIslam.^[6]

After the victory ofJustinian II, Konon was dispatched on a diplomatic mission toAlania andLazica to organize an alliance against theUmayyadcaliphate underal-Walid I. According to the chronicle written byTheophanes the Confessor, Justinian wanted to get rid of Konon and took back the money that had been given to him to help advance Byzantine interests, thus leaving Konon stranded in Alania. The chronicle describes the mission as successful and Konon returning eventually to Justinian after crossing the Caucasus mountains in May withsnowshoes and taking the fortress of Sideron, associated with theTsebelda fortress, on the way.^[7]

Konon was appointed commander (stratēgos) of theAnatolic Theme by EmperorAnastasius II. On his deposition, Konon joined with his colleagueArtabasdos, thestratēgos of theArmeniac Theme, in conspiring to overthrow the new EmperorTheodosius III, ostensibly in support of Anastasius. Artabasdos was betrothed to Konon's daughterAnna.^[8] In 717, Konon marched on Constantinople, capturing Theodosius' son atNicomedia. He forced Theodosius to abdicate, promising safety for him and his family. Theodosius then became amonk atEphesus. On 25 March, abandoning his allegiance to Anastasius, Konon was crowned by PatriarchGermanus I of Constantinople as Emperor Leo III at theHagia Sophia.^[9]

The new emperor was immediately forced to attend to thesecond Arab siege of Constantinople, which commenced in August of the same year. The Arabs were Umayyad forces sent by CaliphSulayman ibn Abd al-Malik and serving under his brotherMaslama ibn Abd al-Malik. They had taken advantage of the civil discord in the Byzantine Empire to bring a force of 80,000 to 150,000 men and a massive fleet to theBosphorus,^[10] intending to seize the Byzantine capital and destroy the Empire with a single overwhelming attack.^[11]

Careful preparations, begun three years earlier under Anastasius II, and the stubborn resistance put up by Leo wore out the invaders. An important factor in the victory of the Byzantines was their use ofGreek fire.^[12] The Arab forces also fell victim to Bulgarian reinforcements arriving to aid the Byzantines. Leo was allied with the Bulgarians but the chroniclerTheophanes the Confessor was uncertain if they were still serving underTervel of Bulgaria or his eventual successorKormesiy of Bulgaria.

Faced with the Bulgarian onslaught, the impenetrability of Constantinople's walls, and their own exhausted provisions, the Arabs were forced to abandon the siege in August 718. Sulayman had died the previous year, and his successorUmar II never made a second attempt to capture the city.^[13] The siege had lasted 12 months.

Having thus saved the Empire from extinction, Leo proceeded to consolidate its administration, which in the previous years of anarchy had become completely disorganized.^[14] In 718 he suppressed a rebellion inSicily.^[15] The following year saw the deposed EmperorAnastasius II raise an army and attempt to retake the throne, but he was captured and executed by Leo's government. The rebellion was the only serious threat to Leo's usurpation.^[16] Umayyad attacks under CaliphHisham ibn Abd al-Malik continued in the form of yearly raids in eastern and centralAsia Minor (see hatched area in figure), which affected communications, commerce and agricultural production. In 721, the city ofDalisandus was captured, followed by the fortresses ofKamachon andIkonion in 723/724 and several frontier fortresses in 725.Caesarea (Cappadocia) was captured in 727, thenGangra in 728. The Byzantine counter-raids were generally of little strategic impact, although crucially a major invading force was destroyed in theBattle of Akroinon of 740. It was only during theThird Fitna of 744–747, a civil war within the Umayyad Caliphate, that the regularity of attacks were temporarily interrupted.^[17]

Leo secured the Empire's frontiers by invitingSlavic settlers into the depopulated districts and by restoring thearmy to efficiency.^[18] His military efforts were supplemented by his alliances with theKhazars and theGeorgians.^[19] However, theLombards exploited the Empire's difficulties beginning in 717, when the duke ofBenevento capturedCumae, the duke ofSpoleto capturedNarni andLiutprand, King of the Lombards, occupiedClasse in theExarchate of Ravenna. Although Narni was never regained, Gregory II recovered Cumae and Liutprand withdrew from Classe. In 724 or 725, Leo increased taxes in Italy which Gregory opposed. This led to two plots to assassinate Gregory, the second of which was supported byExarch Paul, but both were foiled by the Romans with the help of the Lombards of Benevento and Spoleto.^[20]

Leo effected many political and ecclesiastical restructurings in order to bolster the authority of the Empire and thePatriarch of Constantinople. Since the end of the seventh century, imperialstratēgoi were sent to the theme of Sicily (which includedCalabria), and in 732–733 Leo deprived the church of Rome of thepatrimony of St Peter in the theme, reallocating tax income that originally went to the church of Rome to the imperial administration (a large annual sum of 350 pounds of gold). However in 743, Constantine V compensatedPope Zachary for this loss by granting him the estates of Ninfa and Norma to the south of Rome. Between 732 and 754, the bishops of Illyricum,Crete, Sicily, Calabria andNaples (until 769) were transferred from the authority of Rome to Constantinople.^[21] The Isaurians in general saw the church and its patriarchs as subordinate to the imperial will.^[22]

The740 Constantinople earthquake damaged theWalls of Constantinople, the restoration of which Leo paid for out of the imperial treasury, raising the City taxes by 8¹⁄₃ per cent in order to do so, as was recorded on the land walls near theSea of Marmara.^[23][24] The Empire of the eighth century was characterized by ruralization and depopulation, which along with the Arab invasions motivated Leo to undertake intense centralization and militarization, particularly involving the many fortresses and walls in towns such asNicaea andPadyandus.^[25]

Leo III died ofdropsy on 18 June 741 and was buried in theChurch of the Holy Apostles.^[26]

Leo's most striking legislative reforms dealt with religious matters, especiallyiconoclasm ("icon-breaking," therefore an iconoclast is an "icon-breaker").^[29] After an apparently successful attempt to enforce thebaptism of allJews andMontanists in the empire (722), he issued aseries of edicts against the veneration of images (726–729).^[30][31]

A revolt broke out in Greece under the leadership ofAgallianos Kontoskeles, mainly on religious grounds, with a certain Kosmas being declared rival emperor. The imperial fleet quashed the uprising in 727 by way ofGreek fire. In 730, PatriarchGermanus opted to resign rather than subscribe to iconoclasm; Leo replaced him withAnastasius,^[32] who willingly sided with the Emperor on the question of icons. PatriarchJohn V of Jerusalem along withJohn of Damascus fiercely opposed imperial iconoclasm, issuing a pamphlet entitledAdversus Constantinum Caballinum. A later polemical version of the pamphlet attributes to Leo the saying, "I am emperor and priest."^[33]

In theItalian Peninsula, the defiant attitude of PopesGregory II and laterGregory III on behalf of image-veneration led to a fierce quarrel with the Emperor, with theLiber Pontificalis stating that Gregory II "took up arms against the emperor as if against an enemy."^[34] In Rome, the population was more sympathetic to iconodulia, killing a pro-imperial duke and blinding another, while in Naples, iconoclasm was broadly well-received. A conflict between pro- and anti-imperial factions in theExarchate of Ravenna led to the death of Exarch Paul.^[35] The struggle was accompanied by an armed outbreak in the Exarchate in 727, which Leo endeavoured to subdue by means of a large fleet. The new Exarch,Eutychius, disembarked in Naples but could not enter Rome and assert his authority. This led to an unexpected alliance between Liutprand and Eutychius against Gregory, who, however, managed to convince the King, appealing to his piety, to return north and the Exarch to put down a revolt inEtruria led by the usurperTiberius Petasius.^[36] In response to the promulgation of stronger iconoclastic decrees in 730, Gregory II and Gregory III summoned councils inRome to anathematize and excommunicate the iconoclasts (730, 732). Leo retaliated by making the aforementioned transferals inSouthern Italy andIllyricum from the papal diocese to that of thePatriarch of Constantinople.^[37][38]

Scholars offer various explanations for the ban on venerating iconsc. 730. On the basis of Patriarch Germanus' letters read at the 787Second Council of Nicaea, which state that the bishops Constantine ofNakoleia and Thomas ofClaudiopolis had forbidden the veneration of icons even before 730, some scholars argue that the allegedaniconism of the eastern part of the Empire, Leo's place of origin, motivated his policies. The phrase "I am emperor and priest" attributed to Leo by later iconodule polemicists represents the characteristically Isaurian imperial ascendancy over the church, which was rejected in the mid-9th century after PatriarchMethodios I of Constantinople purged the clergy of iconoclasts, asserting the autonomy of the church against the iconoclast emperor,Theophilos (r. 829–842).[39] Others have discussed the mutual influence of Muslim and Byzantine iconoclasm, noting thatCaliphYazid II had issued an iconoclastic edict, also targeting his Christian subjects, already in 721.^[40]

According to historian Marie-France Auzépy, these explanations are insufficient. She appeals to an explanation by Byzantine chroniclers, that a terrifying volcanic eruption atThira in 726 was interpreted by Leo as a manifestation of God's wrath. In theBible, God allows his people to fall toBabylonian captivity because of theiridolatry. Thus, Auzépy says, the banning of the veneration of images was fundamentally a rejection of idolatry in order to ensure the survival of the Christian people of the Empire, a decision which was apparently vindicated by the abatement of the Arab and Bulgar threat during Leo's reign.^[41]

Some scholars, such as Leslie Brubaker and John Haldon, doubt whether there was any active imperial involvement in iconoclasm at all, proposing instead that Leo made a qualified critique of the use of images in public spaces, likely leading to the adoption of a somewhat iconoclastic attitude among the clergy in the late 730s or early 740s.^[42] The notion that there was mass imperial persecution and destruction of images is dismissed as a later "iconophile myth".^[43] Brubaker and Haldon support this hypothesis by pointing to the absence of any reports of iconoclasm in several contemporary accounts, including those ofWillibald, who travelled to Nicaea from 727 to 729, Germanus and evenJohn of Damascus. TheVenerable Bede does refer to a critique of images in Constantinople, and Germanus and John of Damascus say that the clergy was divided on the issue of iconoclasm, however there was no evidence of widespread support for the iconoclastic policies or of systematic removal of images under Leo.^[44] Brubaker and Haldon attribute a more moderate iconoclasm to Leo, "It is quite possible that Leo did attempt to restrict the public display of certain types of image and to remove them from certain places in churches (near thealtar and in theapse, for example) to avoid their receiving the honour due to God alone", confirming this conclusion with the writings of Germanus and John of Damascus which appear to describe a kind of initial or moderate stage of iconoclasm.^[45]

Leo reformed thesilention, a type of restricted council instituted byJustinian I, transforming it into a special assembly in theGreat Palace of Constantinople, in which the emperor would announce a solemn decision.^[46]

Leo undertook a set of civil reforms including the abolition of the system of prepaying taxes which had weighed heavily upon the wealthier proprietors, the elevation of theserfs into aclass of freetenants and the remodelling offamily law,maritime law andcriminal law, notably substitutingmutilation for thedeath penalty in many cases.^[47] These punishments were contrary to the Roman legal tradition, and bear the influence ofcanon law.^[48] The new measures, which were embodied in a newcode called theEcloga (Selection), published in 741, met with some opposition on the part of the nobles and higher clergy. TheEcloga were a revision and abridgement of the sixth-centuryCode of Justinian.^[49] Leo's prologue to theEcloga sets out his conception of law as requiring ethical significance founded upon God's will and divinely-sanctioned imperial authority.^[50] The authors of the legal codes ofBasil I (r. 867–886) andLeo VI the Wise (r. 886–912) of theMacedonian dynasty formally rejected theEcloga.^[51]

Leo and his successorConstantine V transformed the Byzantineorphanotrophos into amagistrate. Prior to these legislative reforms,Byzantine law required that allorphans are passed into the Byzantineorphanage or to amonastery.^[52]

The coins minted during Leo's reign exclusively depicted male imperial dynasts, promoting the dynasticorder of succession.^[53] In 721, Leo introduced themiliarēsion, a silver coin worth one-twelfth of anomisma.^[54] Thegold coins ofLeo IV the Khazar show posthumous portraits of Leo III.^[55]

In response to the catastrophicTwenty Years' Anarchy, Leo, and his son Constantine V in emulation, fundamentally changed the formula of imperial survival as established by Justinian I. The military was closely associated with the regime in order to stifle the possibility of usurpation. Imperial power was also strengthened by the introduction of low-denomination silver coins, allowing greater flexibility in raising taxes. This autocratic renewal of imperial authority was motivated by justice and spiritual welfare, leading to the denunciation and eventual destruction of images deemed to be "idolatrous".^[56] These aspects, which all originate in the personality of Leo, can be attributed to the entire Isaurian dynasty, which was unwaveringly iconoclastic,Irene of Athens excepted. Succeeding generations of the Byzantine ruling class regarded the Isaurian period as one of religious persecution.^[57] The phrase "I am emperor and priest" attributed to Leo by later iconodule polemicists represents the characteristically Isaurian imperial ascendancy over the church, which was rejected in the mid-9th century after PatriarchMethodios I of Constantinople purged the clergy of iconoclasts, asserting the autonomy of the church against the iconoclast emperor,Theophilos (r. 829–842).[58]

The few primary sources of the eighth and ninth centuries were mostly written by clerical or monastic iconodules who were hostile to Leo and Constantine V. They tended to view the period as dominated by ecclesiastical matters and in particular the imperial persecution of iconodules, despite the Empire's contemporaneous existential struggle against its enemies. Modern assessment of the reign of Leo as well as that of his son is that it was a period of violence which saw the Empire's rescue from destruction, within a context of extensive domestic policy reform.^[59] Leo's successful ruse against Caliph Sulayman and his general Maslama, which secured his place on the throne, and then his successful defense of the Empire during the siege of Constantinople, earned him a reputation as a wily and formidable commander against colossal odds.^[60][61] His personal knowledge of the geography of the foothills of theTaurus Mountains helped in the countering of Arab incursions mainly in the latter part of his reign, as was especially signified in the Battle of Akroinon—a crucial victory for Leo which had changed the tide of theArab–Byzantine wars in the favour of Rome for the next 350 years.^[62] However, the Byzantine control over its Italian possessions was steadily weakened during Leo's reign, and his attempts to reassert imperial authority there failed.^[63]

In 1573, a translation ofJohn of Damascus' attack on Leo III was published, under the titleApologie divisée en trois livres contre Léon Isaure, triggering religious controversy.^[64]

With his wifeMaria, Leo III had four known children:

• Constantine V, born in 718. He was crowned co-emperor in 720 and became senior emperor in 741.
• Anna, born before 705. She married the future emperorArtabasdos.^[65]
• Kosmo and Irene. They were both buried in a sarcophagus of Proconnesian marble in the Church of the Apostles.^[66]

• List of Byzantine emperors