Very likely raised during the AD30’s from their homelands in southern Romania and Bulgaria, and then posted to Germany, from where they were gleaned to bolster the Claudian invasion army of Aulus Plautius in AD43. Considering the fate of the hapless Legio IX Hispana (not to mention the thriving towns of Colchester (Camulodunum), Saint Albans (Verulamium) and London (Londinium)) during the Boudican revolt, it is possible that the unit had already been moved elsewhere by AD61, and it may be significant they are next identified at Cirencester (Corinium Dobunnorum) immediately afterwards. The military withdrew from Cirencester (Corinium Dobunnorum) in the late 70’s, and it is possible that the unit were kept in reserve in South Wales until their withdrawal to Lower Germany by the mid-second century, where they apparently were to remain.

Evidence for the presence of Ala Primae Thracum in Britain

1. Burn 95; CIL XVI.48; military diploma, dated: January 19th AD103.
2. Camulodunum (Colchester, Essex; RIB 201; tombstone; probably pre- AD49).
3. Corinium (Cirencester, Gloucestershire; RIB 109; tombstone; c. AD62).
4. Isca Silurum (Caerleon, Gwent; RIB 2415.39; stamped bronze trulla¹; Flavian?).
   1. Plural trullae ladle, scoop; wash-basin.