<P> Soldiers who had served out their time and had obtained their discharge (mission), but had voluntarily re-enlisted, were called evocati . </P> <P> A standard Republican legion before the reforms of Gaius Marius ("the early Republic") contained about 4500 men divided into the velites, the principes, and the hastati--of 1200 men each--also the triarii, of 600 men, and the equities, of 300 men . The first three types stood forward in battle; the triarii stood back . The velites and the equites were used mainly for various kinds of support . </P> <P> The class system of Servius Tullius already had organized society to support the military . He practically had created a "store" in which officers could "shop" for the resources they needed . Officers were elected by the civilian centuries, usually from the classic, or from the patricii if the latter were not included in the classic (there is some question about how this worked). </P> <P> There were available 80 centuries of wealthy classic, 40 of young men ages 17 to 45, and 40 of men 45 and older . These citizens could afford whatever arms and armor the officers thought they needed . The classic could go into any branch of the legion, but generally, veterans were preferred for the triarii, and young men for the velites . The rest was filled out from the young 40 centuries . The older 40 were kept for emergencies, which occurred frequently . These older men were roughly equivalent to the United States Army Reserve . </P>

What were the major stages in the political and military development of the roman republic