Alpine regiments of the Roman army

The Alpine regiments of the Roman army were those auxiliary units of the army that were originally raised in the Alpine provinces of the Roman Empire: Tres Alpes, Raetia and Noricum. All these regions were inhabited by predominantly Rhaetian peoples and Celtic-speaking tribes. They were annexed, or at least occupied, by the emperor Augustus' forces during the period 25–14 BC. The term "Alpine" is used geographically in this context and does not necessarily imply that the regiments in question were specialised in mountain warfare. However, in the Julio-Claudian period (27 BC – AD 68), when the regiments were still largely composed of Alpine recruits, it is likely that they were especially adept at mountain operations.

As would be expected from mountain people, the Alpine provinces predominantly supplied infantry; only one Alpine cavalry ala is recorded. About 26 Alpine regiments were raised in the Julio-Claudian period, the great majority under Augustus or his successor Tiberius (i.e., before AD 37). Of these, six regiments disappeared, either destroyed in action or disbanded, by AD 68. A further two regiments were raised by Vespasian (reigned from 69 to 79 AD). These and the 20 surviving Julio-Claudian units are recorded at least until the mid 2nd century, but by that time only around a quarter were still based in the Alpine provinces or in neighbouring Germania Superior (Upper Rhine area). The rest were scattered all over the empire and would probably have long since lost their ethnic Alpine identity through local recruitment.