Description

As Romans were never considered exceptionally good horsemen, and the role of the cavalry not as important in the Roman thought process, the Equitatus was generally made up of non-Roman horsemen. While they would play an important part of Legionary tactics, the Roman Cavalry was considered secondary and would remain the weakest part of the Roman Army until the very late Imperial period.
Generally, the cavalry was used as light skirmishing troops, and mounted archers whose job was to patrol, act as scouts and messengers and to provide a mobile defensive screen while the legion was massing in battle array. As in all armies throughout history, the mounted trooper was also very effective in chasing down and harassing a fleeing and panicked enemy force.

As part of the military reforms of Augustus around AD 14, the Auxilia were re-organized. They would be trained to the same standards of discipline as the legions. They were mainly drawn from a wide range of warlike peoples throughout the provinces, and would receive Roman citizenship on completion of their 25 year sevice. Senior officers in contrast were Roman citizens.
The Auxilia filled the tasks of patrolling, containing raids, tax collecting, and the multitude of duties of the frontier troops.
They were especially suited to garrison and local policing activities, and could also hold their own in small scale warfare.