Brigantes, in ancient Britain, a tribe conquered by the Romans during the reign of Antoninus Pius (c. ad 155). The Brigantes occupied the region south of the Antonine Wall, extending to the Humber estuary in the east and to the River Mersey in the west. Their chief city was Isurium (Aldborough) and later Eboracum (York); they had forts at Cataractonium (Catterick), Olicana (Ilkley), and Vinovium (Binchester). They were twice defeated by the Romans (c. ad 50 and c. 71) before their final subjection by Antoninus, and during his reign the Brigantes lost even more of their land to the Romans.