Roman metallurgy

Metals and metal working had been known to the people of modern Italy since the Bronze Age. By 53 BCE, Rome had already expanded to control an immense expanse of the Mediterranean. This included nine provinces radiating from Italy to its islands, Spain, Macedonia, Africa, Asia Minor, Syria and Greece, and by the end of the Emperor Trajan's reign, the Roman Empire had grown further to encompass parts of Britain, Egypt, all of modern Germany west of the Rhine, Dacia, Noricum, Judea, Armenia, Illyria and Thrace (Shepard 1993). As the empire grew, so did its need for metals. Metals and metal working had been known to the people of modern Italy since the Bronze Age. By 53 BCE, Rome had already expanded to control an immense expanse of the Mediterranean. This included nine provinces radiating from Italy to its islands, Spain, Macedonia, Africa, Asia Minor, Syria and Greece, and by the end of the Emperor Trajan's reign, the Roman Empire had grown further to encompass parts of Britain, Egypt, all of modern Germany west of the Rhine, Dacia, Noricum, Judea, Armenia, Illyria and Thrace (Shepard 1993). As the empire grew, so did its need for metals. Central Italy itself was not rich in metal ores, leading to necessary trade networks in order to meet the demand for metal from the Republic. Early Italians had some access to metals in the northern regions of the peninsula in Tuscany and Cisalpine Gaul, as well as the islands Elba and Sardinia. With the conquest of Etruria in 275 BC and the subsequent acquisitions due to the Punic Wars, Rome had the ability to stretch further into Transalpine Gaul and Iberia, both areas rich in minerals. At the height of the Roman Empire, Rome exploited mineral resources from Tingitana in north western Africa to Egypt, Arabia to North Armenia, Galatia to Germania, and Britannia to Iberia, encompassing all of the Mediterranean 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 in mineral extraction. This was mirrored in other trades and industries. One of the most important Roman sources of information is the Naturalis Historia of Pliny the Elder who died in the eruption of Mount Vesuvius in 79 AD. Several books (XXXIII–XXXVII) of his encyclopedia cover metals and metal ores, their occurrence, importance and development. Many of the first metal artifacts that archaeologists have identified have been tools or weapons, as well as objects used as ornaments such as jewellery. These early metal objects were made of the softer metals; copper, gold, and lead in particular, as the metals either as native metal 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 fact alloys, the most important being bronze, an alloy of copper and tin. Alloys are mixtures of different metals created either by smelting or by forging. It is important to note that an ore does not necessarily constitute an alloy; ore is a collection of minerals and alloyed metals. 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: Gold, Silver, Copper, Tin, Lead, Zinc, Iron, Mercury, Arsenic, Antimony (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), aversion to corrosion, weight, and countless 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 create pewter, which would prove its utility as cooking and tableware. Iberia or modern Spain and Portugal, was one of if not the richest Roman province in the case of mineral ore from around the first century BC (Healy 1978). Containing deposits of the metals (Gold, Silver, Copper, Tin, Lead, Iron, and Mercury), it was very rich in resources. The Romans realised this, and there is evidence of large-scale mining and processing in the region. From its acquisition during the Punic Wars to the Fall of Rome, Iberia continued to produce a significant amount of Roman metals (Healy 1978, Shepard 1993). Similarly, Britannia was also very rich in metals. Gold was mined at Dolaucothi in Wales, copper and tin in Cornwall, and lead in the Pennines, Mendip Hills and Wales. Significant studies have been made on the iron production of Roman Britain; iron use in Europe was intensified by the Romans, and was part of the exchange of ideas between the cultures through Roman occupation (Aitchison, 1960). 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 into the Iron Age. Noricum is the ancient site of modern Austria. Exceedingly rich in gold and iron ore, Pliny, Strabo, and Ovid all lauded its bountiful deposits. Iron was its main commodity, but alluvial gold was also prospected. The province itself had been assimilated into the Empire through prolonged peaceful contact from 181 BC when the Romans colonised Aquileia, a major trading centre between the two nations. By 15 BC, Noricum was officially made a province of the Empire, and the metal trade saw prosperity well into the fifth century AD (Shepard 1993, Healy 1978). Some scholars believe that the art of iron forging 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 (Aitchison, 1960). 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 distributed slag material) and steel (carbonised iron) categories, as pure iron is too soft to function like wrought or steel iron (Sim 1999, Aitchison 1960).