What was the role of mercenaries in the Roman army?

The Roman army was one of the most formidable fighting forces in the ancient world, and its success can be attributed in part to its use of mercenaries. Mercenaries were hired soldiers who were not citizens of Rome, but were instead paid to fight for the empire. The role of mercenaries in the Roman army varied depending on the time period and the specific circumstances of each conflict.

During the early days of the Roman Republic, mercenaries were used primarily as auxiliary troops to supplement the army's regular legions. These troops were often drawn from neighboring tribes and kingdoms, and they were used to provide additional manpower and specialized skills, such as archery and cavalry.

As the Roman Empire expanded, the role of mercenaries became more complex. Mercenaries were used to garrison conquered territories and to suppress rebellions, as well as to fight in the empire's many wars of conquest. The empire also began to rely on entire mercenary armies, such as the Germanic foederati, who were given land and status in return for their military service.

Despite their important role in the Roman army, mercenaries were often viewed with suspicion by Roman citizens. This was partly because mercenaries were seen as less loyal and less disciplined than regular soldiers, and partly because they often fought for Rome's enemies as well as for Rome itself. Nonetheless, mercenaries continued to be an integral part of the Roman army until the empire's collapse in the 5th century AD.