The unit was named after a former commander, Julius Indus, sometime after AD21. The only record of this ala in Britain is the tombstone of an eques from Cirencester, undated, but placed on stylistic grounds to the late first century (c. AD70+). It is very likely that this unit were a part of the initial Claudian invasion army, though not proven. It is possible that they left the island with Julius Agricola in 84, they had certainly gone by the turn of the second century, as they are recorded on a diploma from Lower Germany in 98, and were moved to Upper Germany by 134.
Evidence for the presence of Ala Gallorum Indiana in Britain
- Corinium (Cirencester, Gloucestershire; RIB 108; tombstone)