proletarii
PROLETA´RIIThe state, according to the Servian constitution, was divided into those who had property (locupletes) arranged in classes, and those who had not and were outside these classes; these unclassed citizens were called capite censi, i.e. reckoned by heads, or proletarii, i.e. begetters of children (Cic. de Rep. 2.2. 2, 40; Gell. 16.10). These included all who were assessed at not more than 1500 asses: the distinction in civil matters is marked by the law of the Twelve Tables, that for a proletarius any one might act as vindex, while for the adsiduus (or locuples) an adsiduus was required [ACTIO]. As to their military service, see EXERCITUSVol. 1. p. 781. (Mommsen, Rom. Hist. 1.196; Staatsrecht, 3.238.)
[G.E.M]The name in the Roman centuriate system (see comitia) of those citizens who were placed in the lowest of the five property classes, and who were exempt from military service and tribute. Their name owes its origin to the fact that they only benefited the State by their children (proles). Another name for them is capite censi— i. e. those who were classed in the list of citizens at the census solely in regard to their status as citizens (caput). Afterwards, the richer among them were taken to serve in the wars: these were then called proletarii; and those without any property at all, capite censi. In and after the time of Marius, when the levy of troops was no longer founded on the census, the Roman armies were recruited by preference from the last class. See Mommsen, Staatsrecht, iii. 238.