Aerarii
By the constitution of Servius Tullius (see
Centuria), aerarii were citizens who were not settled on land of their own, and
therefore not included in any one of the property classes founded on land-ownership. The term
was also applied to those standing outside of the tribal union, who were excluded from the
right of voting and from military service, and who were bound to pay a poll-tax in proportion
to their means. Citizens in the classes and tribes could be expelled from their tribe by the
censors in punishment for any fault, and placed among the aerarii. But when the latter were
likewise admitted into the tribes (B.C. 308), being enrolled in the city tribes (B.C. 304),
which were on that account less esteemed than the country ones, a penal transfer to the
aerarii consisted in expulsion from one's proper tribe and removal to one of the city tribes
till at least the next census.