What happened to all the British lead?

Leadd ingot in the Grosvenor Museum,
Chester  (foto: B.Hoffmann)

The lead industry of Roman Britain is a well-studied field. From the study of the inscription on the Lead ingots in Roman Inscriptions of Britain, to the numerous mining archaeological studies on the lead mines throughout Britain from the Mendips in the South, to the Flintshire hills and their association with the Legio XX in Chester to the Lead mines in the Pennines in Derbyshire and in the northern Pennines around the Roman fort of Whitley Castle to the more recently recognized exploitation of the lead and silver in the Scottish Lowlands around Drumlanrig.

Britain is rich in silver and even richer in lead, especially as many of the local ores, such as galena, contain both. But where did it all go to? It is an interesting fact that Romano-British sites, especially military ones, produce more lead than many of their continental counterparts, but this only accounts for a small part of what must have been produced in the 300 odd years of Roman mining in the island. 

A recent article by the team of the Bergbau Museum Bochum and the German Archaeological Institute (DAI) is actually shedding an interesting spotlight on this issue. During their work on the Corpus of Roman lead ingots they catalogued six lead ingots from a shipwreck in Corsica, that had stamped inscriptions of the Legio VI Victrix (for most of its history stationed in York), and are thus likely to have originated in Britain.

They complement four further French ingots from Cabillonum/Chalons-sur-Saone and Lillebonne/Juliobona, whose cast inscriptions allow them to be dated to 197/198AD after the victory of Septimius Severus over Clodius Albinus and which have been known for a long time. Some of these mention Legio XX from Chester (CIL XIII 2612b, p. 409)

Lead isotope analysis suggests an origin of the lead of these ingots from either the Mendips or the Flint mountains, while the silver-lead relationship suggests that they may not have been desilvered. 

This has a number of interesting implications: First of all, it shows that the army continued to be involved in the exploitation of lead after the first century, possibly even in the Mendip hills, where civilian contractors are known in the first century AD.

The suggestion that the lead may not have been desilvered, furthermore, suggests that by the third century at least some of the mining was actually targeting the lead itself, and was no longer just seen as a very useful byproduct of the silver mining. 

The occurrence of the British lead in Gaul and off the coast of Corsica also shows that at least by the third century lead (and not just the more valuable silver and gold) were exported from Britain, certainly as far as the Mediterranean and possible even for use at Rome itself (Corsica is on a well-travelled route from the South of France to the harbours of Central Italy, especially Ostia). Given the weight of the ingots and the fact that there are lead deposits closer to the Italy (eg. along the Rhine and in Spain), this may surprise and it would be easy to see this as an exception in the aftermath of the Clodius Albinus uprising. 

On the other hand the trade route from the Atlantic ports via the large French rivers (most famously the Garonne, but also perhaps the Loire and Seine) was well established since at least the Iron Age and the lead may have provided an interesting heavy export article that could serve as ballast as well as trade good on the return journey of the ships bringing Mediterranean wine and oil to Britain. 

Further Reading:

B.Jones and D.Mattingly (1990), An Atlas of Roman Britain. Oxford: Blackwell.

Norbert Hanel - Peter Rothenhöfer - Michael Bode - Andreas Hauptmann, Britannisches Blei auf dem Weg nach Rom. Die Metallversorgung der Reichsmetropole am Beginn der Herrschaft des L. Septimius Severus. Skyllis 13,1, 2013, 38-42.