This regiment was a five-hundred strong mixed unit of cavalry and infantry, recruited from the among the Astures tribe of Northern Spain. Evidently stationed at the Llanio fort in South Wales in the first and perhaps second centuries, their presence is next recorded claiming credit for rebuilding the granary of the fort at Great Chesters on Hadrian's Wall in Northumberland. The unit is listed as the garrison of Great Chesters in the Notitia Dignitatum during the late-fourth century, but was here mistakenly attributed the numeral I primae.
