Oppidum

An oppidum (plural oppida) is a large fortified Iron Age settlement. Oppida are associated with the Celtic late La Tène culture, emerging during the 2nd and 1st centuries BC, spread across Europe, stretching from Britain and Iberia in the west to the edge of the Hungarian plain in the east. They continued in use until the Romans began conquering Europe. North of the River Danube, where the population remained independent from Rome, oppida continued to be used into the 1st century AD.

Oppidum is a Latin word meaning the main settlement in any administrative area of ancient Rome. The word is derived from the earlier Latin ob-pedum, "enclosed space", possibly from the Proto-Indo-European *pedóm-, "occupied space" or "footprint".

In his Commentarii de Bello Gallico, Julius Caesar described the larger Celtic Iron Age settlements he encountered in Gaul during the Gallic Wars in 58 to 52 BC as oppida. Although he did not explicitly define what features qualified a settlement to be called an oppidum, the main requirements emerge.

They were important economic sites, places where goods were produced, stored and traded, and sometimes Roman merchants had settled and the Roman legions could obtain supplies. They were also political centres, the seat of authorities taking decisions that affected large numbers of people, such as the appointment of Vercingetorix as head of the Gallic revolt in 52 BC.

Caesar named 28 oppida. By 2011, only 21 of these had been positively identified by historians and archaeologists: either there was a traceable similarity between the Latin and the modern name of the locality (e.g. Orléans-Cenabum), or excavations had provided the necessary evidence (e.g. Alesia). Most of the places that Caesar called oppida were city-sized fortified settlements. However, Geneva, for example, was referred to as an oppidum, but no fortifications dating to this period have yet been discovered there. Caesar also refers to 20 oppida of the Bituriges and 12 of the Helvetii, twice the number of fortified settlements of these groups known today. That implies that Caesar likely counted some unfortified settlements as oppida. A similar ambiguity is in evidence in writing by the Roman historian Livy, who also used the word for both fortified and unfortified settlements.

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