Can citizens join Auxilia to be in cavalry?

[Mrbsct]

Hey I am wondering if a Roman citizen could choose not be a foot soldier in the Legion and join the Barbarian Auxilia to be in the cavalry?

Also when did The Roman empire start to use citizen cavalry after Dioclecian(Legions and Auxilia system was disbanded for Cominitenes) can citizens serve in Comintenes cavalry or was it all Foeterttii?

[D B Campbell]

Hey I am wondering if a Roman citizen could choose not be a foot soldier in the Legion and join the Barbarian Auxilia to be in the cavalry?

A citizen could certainly choose to serve in the auxilia, where the standards appear to have been less exacting. As an alternative, a legionary could achieve promotion, first into the legionary cavalry, and then across into a cavalry ala as an officer (the route followed by the well-known Tiberius Claudius Maximus). That way, you get more respect and more pay.

[Marja]

Also, there were alae of Roman citizens. I'm not sure whether any were formed this way, or whether all were formed from non-citizens and later granted the new status, but several cohorts of volunteers were formed as cohorts of Roman citizens.