The First Cohort of Nervii was raised from among the Nervii tribe of Belgic Gaul. These warlike neighbours of the Tungri had almost defeated Julius Caesar and were severely put-down in response, though they were later to provide the Roman auxiliary forces with foot soldiers of excellent repute. They are attested at Caer Gai in on a tombstone of a former Blacksmith in the unit. They are also named on a single undated altar from Netherby in Cumbria and were probably stationed at the fort during its first period of occupation as a Hadrianic outpost.

Evidence for the presence of Cohors Primae Nerviorum in Britain

1. Military Diplomata – Late AD105
2. Caer Gai (RIB 418 tombstone).
3. Netherby (RIB 966 altar).
4. Chesterholm (RIB 1683 altar).