This is a list of Roman legions. These are mainly legions of the Roman Empire; earlier legions were not permanent named organizations.
Comments added include life span of the legion, cause of disappearance (if relevant) and the original commander, meaning, the man who levied the legion.
Later on, in the 4th century, the legions lose the role of backbone of the Roman armies in favour of the cavalry units; their new role is the one of static control of the borders of the empire, guarding the fortified garrisons in the zones most exposed to enemy invasion. Some of these new legions are known: