Called miles ("soldier") or legionarius in Latin, the Roman legionary was (usually) a Roman citizen under 45 years of age. The soldier enlisted in a legion for twenty-five years of service, a change from the early practice of enlisting only for the duration of a campaign. The last five years were on veteran lighter duties.
On the march in unfriendly terrain the legionary would be loaded down with between three and fourteen days worth of food, armour (lorica segmentata) and shield (scutum), helmet, two javelins (one heavy pilum and one light), short sword (gladius), dagger (pugio), a waterskin and some tools.
The Roman soldier was trained especially hard, discipline was the base of the army's success and the soldiers were relentlessly and constantly trained both with weapons but especially with drill - forced marches with full load and in tight formation were frequent. Discipline was important and infractions were heavily punished by the centurions.