The Roman legion was the largest military unit of the Roman army, a full strength legion generally consisted of 5,600 infantry and 200 auxilia in the period of the Roman Empire (27 BC – AD 1453)

It is difficult to determine whether non-combatants like field surgeons and clerks were included in this 5,300 or helped bring the total number of men up to the official 6,000.

See The Roman Army: Tactics, Organization, and Command Structure.