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Metals andmetal working had been known to the people of modernItaly since theBronze Age. By 53 BC,Rome had expanded to control an immense expanse of the Mediterranean. This included Italy and its islands,Spain,Macedonia,Africa,Asia Minor,Syria andGreece; by the end of the EmperorTrajan's reign, theRoman Empire had grown further to encompass parts ofBritain,Egypt, all of modernGermany west of the Rhine, Dacia,Noricum,Judea,Armenia,Illyria, andThrace (Shepard 1993).^[1] As the empire grew, so did its need for metals.

Central Italy itself was not rich in metal ores, leading to necessarytrade networks in order to meet the demand for metal. Early Italians had some access to metals in the northern regions of the peninsula inTuscany andCisalpine Gaul, as well as the islandsElba andSardinia. With the conquest ofEtruria in 275 BC and the subsequent acquisitions due to thePunic Wars, Rome had the ability to stretch further intoTransalpine Gaul and Iberia, both areas rich in minerals. At the height of the Empire, Rome exploited mineral resources fromTingitana in north western Africa to Egypt,Arabia to North Armenia,Galatia toGermania, and Britannia to Iberia, encompassing all of theMediterranean coast. Britannia, Iberia, Dacia, and Noricum were of special significance, as they were very rich in deposits and became major sites of resource exploitation (Shepard, 1993).

There is evidence that after the middle years of the Empire there was a sudden and steep decline inmineral extraction. This was mirrored in other trades and industries.

One of the most important Roman sources of information is theNaturalis Historia ofPliny the Elder. Several books (XXXIII–XXXVII) of hisencyclopedia cover metals and metal ores, their occurrence, importance and development.

Many of the first metal artifacts that archaeologists have identified have beentools orweapons, as well as objects used as ornaments such asjewellery. These early metal objects were made of the softer metals;copper,gold, andlead in particular, either asnative metals or by thermal extraction from minerals, and softened by minimal heat (Craddock, 1995). While technology did advance to the point of creating surprisingly pure copper, most ancient metals are in factalloys, the most important beingbronze, an alloy of copper andtin. As metallurgical technology developed (hammering,melting,smelting,roasting,cupellation,moulding,smithing, etc.), more metals were intentionally included in the metallurgical repertoire.

By the height of the Roman Empire, metals in use included:silver,zinc,iron,mercury,arsenic,antimony, lead, gold, copper, tin (Healy 1978). As in the Bronze Age, metals were used based on many physical properties: aesthetics,hardness, colour, taste/smell (for cooking wares), timbre (instruments), resistance tocorrosion, weight (i.e., density), and other factors. Many alloys were also possible, and were intentionally made in order to change the properties of the metal; e.g. the alloy of predominately tin with lead would harden the soft tin, to createpewter, which would prove its utility as cooking andtableware.

Iberia (modernSpain andPortugal) was possibly theRoman province richest in mineralore, containing deposits of gold, silver, copper, tin, lead, iron, and mercury.^[2] From its acquisition after theSecond Punic War to the Fall of Rome, Iberia continued to produce a significant amount of Roman metals.^[3]

Britannia was also very rich in metals. Gold was mined atDolaucothi inWales, copper and tin inCornwall, and lead in thePennines,Mendip Hills and Wales. Significant studies have been made on theiron production ofRoman Britain; iron use in Europe was intensified by the Romans, and was part of the exchange of ideas between the cultures throughRoman occupation.^[4] It was the importance placed on iron by the Romans throughout the Empire which completed the shift from the few cultures still using primarily bronze^[who?] into theIron Age.^{[citation needed]}

Noricum (modernAustria) was exceedingly rich in gold and iron, Pliny,Strabo, andOvid all lauded its bountiful deposits. Iron was its main commodity, butalluvial gold was also prospected. By 15 BC, Noricum was officially made aprovince of the Empire, and the metal trade saw prosperity well into the fifth century AD.^[5] Some scholars believe that the art of ironforging was not necessarily created, but well developed in this area and it was the population of Noricum which reminded Romans of the usefulness of iron.^[6] For example, of the three forms of iron (wrought iron,steel, and soft), the forms which were exported were of the wrought iron (containing a small percentage of uniformly distributedslag material) and steel (carbonised iron) categories, as pure iron is too soft to function like wrought or steel iron.^[7]

Dacia, located in the area ofTransylvania, was conquered in 107 AD in order to capture the resources of the region for Rome. The amount of gold that came into Roman possession actually brought down thevalue of gold. Iron was also of importance to the region. The difference between the mines of Noricum and Dacia was the presence of aslave population as a workforce.^[8]

The earliest metal manipulation was probably hammering (Craddock 1995, 1999), where copper ore was pounded into thin sheets. The ore (if there were large enough pieces of metal separate from mineral) could bebeneficiated ('made better') before or after melting, where theprills of metal could be hand-picked from the cooled slag.Melting beneficiated metal also allowed earlymetallurgists to usemoulds and casts to form shapes ofmolten metal (Craddock 1995). Many of the metallurgical skills developed in the Bronze Age were still in use during Roman times. Melting—the process of using heat to separate slag and metal, smelting—using a reduced oxygen heated environment to separate metal oxides into metal and carbon dioxide, roasting—process of using an oxygen rich environment to isolate sulphur oxide from metal oxide which can then be smelted,casting—pouring liquid metal into a mould to make an object, hammering—using blunt force to make a thin sheet which can be annealed or shaped, and cupellation—separating metal alloys to isolate a specific metal—were all techniques which were well understood (Zwicker 1985, Tylecote 1962, Craddock 1995). However, the Romans provided few new technological advances other than the use of iron and the cupellation andgranulation in the separation ofgold alloys (Tylecote 1962).

Whilenative gold is common, the ore will sometimes contain small amounts of silver and copper. The Romans utilised a sophisticated system to separate these precious metals. The use of cupellation, a process developed before the rise of Rome, would extract copper from gold and silver, or an alloy calledelectrum. In order to separate the gold and silver, however, the Romans would granulate the alloy by pouring the liquid, molten metal into cold water, and then smelt the granules withsalt, separating the gold from the chemically alteredsilver chloride (Tylecote 1962). They used a similar method to extract silver from lead.

While Roman production became standardised in many ways, the evidence for distinct unity offurnace types is not strong, alluding to a tendency of the peripheries continuing with their own past furnace technologies. In order to complete some of the more complex metallurgical techniques, there is a bare minimum of necessary components for Roman metallurgy: metallic ore, furnace of unspecified type with a form ofoxygen source (assumed by Tylecote to be bellows) and a method of restricting said oxygen (a lid or cover), a source offuel (charcoal fromwood or occasionallypeat), moulds and/orhammers andanvils for shaping, the use ofcrucibles for isolating metals (Zwicker 1985), and likewise cupellation hearths (Tylecote 1962).

There is direct evidence that the Romans mechanised at least part of the extraction processes. They used water power fromwater wheels for grinding grains and sawing timber or stone, for example. A set of sixteen such overshot wheels is still visible atBarbegal nearArles and dates from the 1st century AD or possibly earlier, the water being supplied by the main aqueduct to Arles. It is likely that the mills supplied flour for Arles and other towns locally. Multiple grain mills also existed on theJaniculum hill in Rome.

Ausonius attests the use of a water mill for sawing stone in his poemMosella from the 4th century AD. They could easily have adapted the technology to crush ore usingtilt hammers, and just such is mentioned by Pliny the Elder in hisNaturalis Historia dating to about 75 AD, and there is evidence for the method from Dolaucothi inSouth Wales. The Roman gold mines developed from c. 75 AD. The methods survived into the medieval period, as described and illustrated byGeorgius Agricola in hisDe re metallica.

They also usedreverse overshot water-wheels for draining mines, the parts being prefabricated and numbered for ease of assembly. Multiple set of such wheels have been found in Spain at the Rio Tinto copper mines and a fragment of a wheel at Dolaucothi. An incomplete wheel from Spain is now on public show in theBritish Museum.

The invention and widespread application ofhydraulic mining, namelyhushing and ground-sluicing, aided by the ability of the Romans to plan and execute mining operations on a large scale, allowed various base and precious metals to be extracted on a proto-industrial scale only rarely matched until theIndustrial Revolution.^[9]

The most common fuel by far for smelting and forging operations, as well as heating purposes, was wood and particularly charcoal, which is nearly twice as efficient.^[10] In addition,coal was mined in some regions to a fairly large extent: almost all major coalfields in Roman Britain were exploited by the late 2nd century AD, and a lively trade along the EnglishNorth Sea coast developed, which extended to the continentalRhineland, wherebituminous coal was already used for the smelting of iron ore.^[11] The annual iron production atPopulonia alone accounted for an estimated 2,000^[12] to 10,000 tons.^[13]

Annual metal production in metric tons

	Output per annum	Comment
Iron	82,500t[14]	Based on estimate of iron production at 1.5 kg per head in Roman Britain, extrapolated to population size of 55 million for entire empire[15]
Copper	15,000 t[16]	Largest preindustrial producer.[17]
Lead	80,000 t[18]	Largest preindustrial producer.[19]
Silver	11,200 t[20]	At its peak around the mid-2nd century AD, Roman stock is estimated at 10,000 t, five to ten times larger than the combined silver mass ofmedieval Europe and theCaliphate around 800 AD.[21]
Gold	11,119 t[22]	Production inAsturia,Callaecia, andLusitania (all Iberian Peninsula) alone. This articleneeds additional citations forverification. Relevant discussion may be found on thetalk page. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Roman metallurgy" – news ·newspapers ·books ·scholar ·JSTOR(April 2023) (Learn how and when to remove this message)

Romans used many methods to create metal objects. LikeSamian ware, moulds were created by making a model of the desired shape (whether through wood,wax, or metal), which would then be pressed into aclay mould. In the case of a metal or wax model, once dry, theceramic could be heated and the wax or metal melted until it could be poured from the mould (this process utilising wax is called the “lost wax“ technique). By pouring metal into the aperture, exact copies of an object could be cast. This process made the creation of a line of objects quite uniform. This is not to suggest that the creativity of individual artisans did not continue; rather, unique handcrafted pieces were normally the work of small, rural metalworkers on the peripheries of Rome using local techniques (Tylecote 1962).

There is archaeological evidence throughout the Empire demonstrating the large scaleexcavations, smelting, and trade routes concerning metals. With the Romans came the concept ofmass production; this is arguably the most important aspect of Roman influence in the study of metallurgy. Three particular objects produced en masse and seen in thearchaeological record throughout the Roman Empire are brooches calledfibulae, worn by both men and women (Bayley 2004),coins, andingots (Hughes 1980). These cast objects can allowarchaeologists to trace years ofcommunication, trade, and even historic/stylistic changes throughout the centuries of Roman power.

When the cost of producing slaves became too high to justify slavelabourers for the manymines throughout theempire around the second century, a system ofindentured servitude was introduced forconvicts. In 369 AD, a law was reinstated due to the closure of many deep mines; the emperorHadrian had previously given the control of mines to private employers, so that workers were hired rather than working out of force. Through the institution of this system profits increased (Shepard 1993). In the case of Noricum, there is archaeological evidence of freemen labour in the metal trade andextraction throughgraffiti on mine walls. In this province, many men were givenRoman citizenship for their efforts contributing to the procurement of metal for the empire. Both privately owned and government run mines were in operation simultaneously (Shepard 1993).

From the formation of the Roman Empire, Rome was an almost completely closedeconomy, not reliant onimports although exotic goods fromIndia andChina (such asgems,silk andspices) were highly prized (Shepard 1993). Through the recovery ofRoman coins and ingots throughout theancient world (Hughes 1980),metallurgy has supplied thearchaeologist withmaterial culture through which to see the expanse of theRoman world.

• Georgius Agricola
• Mining in Roman Britain
• Mining in ancient Rome
• Roman engineering
• Roman technology
• Malvesa

General

Output

• Butcher, Kevin, Matthew Ponting, Jane Evans, Vanessa Pashley, and Christopher Somerfield.The Metallurgy of Roman Silver Coinage: From the Reform of Nero to the Reform of Trajan. Cambridge: Cambridge University Press, 2014.
• Corretti,Benvenuti. "Beginning of iron metallurgy in Tuscany, with special reference toEtruria mineraria."Mediterranean archaeology 14 (2001): 127–45.
• Healy, John F.Mining and metallurgy in the Greek and Roman world. London: Thames and Hudson, 1978.
• Hobbs, Richard.Late Roman Precious Metal Deposits, C. AD 200-700: Changes Over Time and Space. Oxford: Archaeopress, 2006.
• Montagu, Jennifer.Gold, Silver, and Bronze: Metal Sculpture of the Roman Baroque. Princeton: Princeton University Press, 1996.
• Papi, Emanuele., and Michel Bonifay.Supplying Rome and the Empire: The Proceedings of an International Seminar Held At Siena-Certosa Di Pontignano On May 2-4, 2004, On Rome, the Provinces, Production and Distribution. Portsmouth, RI: Journal of Roman Archaeology, 2007.
• Rihll, T. E.Technology and Society In the Ancient Greek and Roman Worlds. Washington, D.C.: American Historical Association, Society for the History of Technology, 2013.
• Schrüfer-Kolb, Irene.Roman Iron Production In Britain: Technological and Socio-Economic Landscape Development Along the Jurassic Ridge. Oxford: Archaeopress, 2004.
• Strong, Donald Emrys (1966).Greek and Roman Gold and Silver Plate (1st ed.). London: Methuen.ISBN 978-0-297-77267-5.
• Young, Suzanne M. M.Metals In Antiquity. Oxford, England: Archaeopress, 1999.

• History of metallurgy
• Industry in ancient Rome
• Ancient Roman metalwork

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