The only concrete evidence of this unit in Britain is a tombstone (possibly two) from Brecon Gaer in South Wales, tentatively dated to the early 2nd century ad. This cavalry wing may also be included on the military diploma CIL VII.1195.

Evidence for The Ala in Britain

1. CIL VII.1195 privilegia militvm; dated: September 16th ad124.
2. Cicucium (Brecon Gaer, Powys; RIB 405 (& possibly 404); tombstone(s); early 2nd. C. ad).