The Comitia was the assembly of the Roman people convened by a magistrate in order to put a question to them and obtain the binding response. The earliest political organization of the Roman people was based on its division into 30 patrician curiae (ten to each of three tribes). The legislative assembly of these curiae, which voted as a body, came to be called the comitia curiata. It conferred the imperium and potestas upon magistrates after their election, it inaugurated certain priests, and it regulated the internal affairs of the curiae. But it had become a mere formality by the time of the Punic Wars.
Meanwhile the plebeians had won the right to become freeholders of land. This made them liable for military service, and they were enrolled accordingly in the military units called centuhae. The resultant body was the comitia centuriata, which was the principal Roman assembly from about 486 until 287 BC. It elected the higher magistrates, passed laws submitted to it by the senate, declared war, and tried capital cases.
The comitia centuriata, however, was found inadequate for the expression of plebeian claims, and the creation of the tribunate (493 BC) led to the establishment of an exclusively plebeian assembly known as concilium plebis (471 BC). It was organized on the basis of another division of the people into 30 territorial tribes; its functions were to elect the plebeian magistrates, to try cases of injury to the latter, and to present petitions through the consuls to the comitia centuriata. Finally, by the Lex Hortensia (287 BC) its decisions (plebiscita) obtained the force of law binding the whole community.
The tribal organization was next extended to the entire people, giving rise to the comitia tributa, which first appears as a legislative assembly in 357 BC and whose rights gradually increased. It elected the inferior magistrates; tried and punished by fine various civil affairs, and also cases of neglect of duty on the part of magistrates, embezzlement of public funds and mismanagement of a war. As regards legislative functions, the comitia tributa had at first only the right to frame resolutions for submission to the senate; but in the later republic it was the usual source of leges passed by the whole people.