This unit was recruited from among the various tribes of the province of Raetia, which comprised parts of western Austria, south-eastern Germany and the south-western Czech Republic. Cohors Quintae Raetorum is mentioned in Britain on a military diploma from AD122 which includes the unit among the northern army of governor Aulus Platorius Nepos. They are also mentioned on a single altarstone to the goddess Coventina recovered from the environs of the fort at Carrawburgh on Hadrian's Wall. Their activities following the Hadrianic period are unknown.
