A tribus, or tribe, was a division of the Roman people for military, censorial, and voting purposes. When constituted in the comitia tributa, the tribes were the voting units of a legislative assembly of the Roman Republic.
According to tradition, the first three tribes were established by Romulus; each was divided into ten curiae, or wards, which were the voting units of the comitia curiata. Although the curiae continued throughout Roman history, the three original tribes that they constituted gradually vanished from history.