The iron metallurgy in Switzerland during the Roman period
During the Roman Period, iron became a very common material and has been used for allmost every purpose. Weapons and tools were still made of iron and they became more and more heavy (as for example the anvils recovered at Vidy and Avenches VD). The Romans used also an incredible quantity of nails for building. The amount of iron required for the roman way of life is much more important than what has been previously assumed.
The archaeological evidences for iron working and smithing are very numerous in roman Switzerland. Smithing slags are found on many sites, including large towns (coloniae : Avenches VD, Augst AG/BL), small towns (Geneva GE, Martigny VS), military settlements (Vindonissa AG, Zurzach AG), villages (vici : Vidy-Lausanne VD, Baden AG, Petinesca BE, Oberwinthetur ZH), hamlets (Marsens FR, Gamsen VS, Alle JU), large agricultural estates (villae : Etagnières VD, Châbles FR, Morat FR, Biberist SO, Rödersdorf SO, Dietikon ZH, Neftenbach ZH, Seeb ZH) and even in smaller farms (Cuarny VD, Boécourt JU). Iron smithing was really a common activity everywhere. Several well preserved workshops have been recently excavated and studied in some details.
Surprisingly, there is no firm evidence for iron production during the 1st and 2nd century AD. There only exist few traces of a late roman production in the area of Romainmôtier VD (site of Les Bellaires - Prins Bois) and Montcherand VD. A bloomery furnace has been excavated near a roman villa in Laufen BL but the dating remains questionable. The possibility to find roman slag heaps near Vindonissa can not be ruled out, as for the area of the Salève mountain (near Geneva in France). Regarding the enormous quantity of iron needed by the inhabitants of Switzerland during the Roman period, it is absolutely certain that the local production never could fulfil the needs. Massive imports of iron must have been the rule. Large centres of iron production dating of the Roman age are well known in France (Montagne Noire, Burgundy etc.). Recent finds of shipwrecks filled with iron bars in southern France illustrate the importance of the roman iron trade.