THE CENSUS IN ANCIENT ROME
The core of the new arrangement was the regular compilation of a list of adult male Romans, in which they were classified by wealth and by residence, rather than by kinship. In the world of the city-state, citizens provided their own arms and armor when serving in the city’s army. Aristocrats clearly possessed the resources to equip themselves in this man ner they certainly could afford to deposit military equipment in their tombs— and they may have supplied weapons and armor to their followers too. Tullius’ census divided Romans into those who could afford to equip themselves for service on foot (known as the classis, “those summoned”), and those who could not (infra classem, “below those summoned”).
Citizens who belonged to the classisprobably along with those who could serve in the cavalry, and just possibly those who were judged to be infra classem also were further subdivided into units known as centuries (centuriae; singular, centuria). In the strictest sense, the term centuria should denote a group of exactly one hundred men; however, in later periods at least, the size of a centuria could be quite different from this supposed norm.
Units likewise termed centuriae also occupied a primary position in the orga-nization of Rome’s armies in the field, and in fact the use of the term in this military context almost certainly preceded its adoption for the census. Roman com-manders raised armies by summoning citizens to gatherings where they chose their soldiers from those eligible to serve. The force raised in this way was called a legion (legio; plural, legiones), which signified that it stemmed from a selection process the verb legere meaning either “to collect” or “to pick”. Under the kings, the legion selected each year was the army of the city. In later centuries, the term came to denote a unit of several thousand men serving under one of the comman-ders who held office for the year (see Chapter Three). From the earliest period for which we have information, a legion was always subdivided into sixty centuries. The centuries of the census, however, were not the same as the centuries of the legion. Later, for certain, the former came to comprise voting units in one type of citizen assembly and this function may even have been original, so that from the outset this “assembly of centuries” represented the citizenry under arms.