The Roman canton, on both banks of the Tiber, concentrated itself on the city earlier than others. The citizens consisted of the families which constituted the larger groups of clans or gentes, formed into those tribes. The remainder of the population were their dependents or slaves. At the head of the family was the father, and the whole community had its king, standing to it in the same relation as the father to the family. His power, within the law, was absolute; but he could not override it or change it on his own authority. This required the formal assent of the assembled citizens. The heads of the clans formed a separate body--the Senate--which controlled the appointment of the king, and could veto legislation. By admission of aliens and absorption of other communities, swelling the number of dependents, was gradually created a great body of plebeians, non-citizens, who began to demand political rights; and whom it was necessary to organise for military purposes which was done by the "Servian Constitution." Gradually Rome won a supremacy in the Latin League, a position of superiority over the aggregate of the other cantons. In this community arose three political movements: (1) On the part of the full citizen, patricii, to limit the power not of the state, but of the kings; (2) of the non-citizens, to acquire political rights; (3) of antagonism between the great landholders and the land-interests opposed to them. The first resulted in the expulsion of the monarchs, and the substitution of a dual kingship held for one year only. But in many respects their joint power was curtailed as compared with that of the monarch, while for emergencies they could appoint a temporary dictator. The change increased the power of the General Assembly, to which it became necessary to admit the non-citizen freeholders who were liable to military duties. The life tenure of the members of the Senate greatly increased the powers of that body, and intensified the antagonism of the patriarch and the plebeians. At the same time, a landed nobility was developing; and when fresh land was acquired by the state, the Patricians claimed to control it. But the great agricultural population could not submit to this process of land absorption, and the consequent strife took the form of a demand for political recognition, which issued in the appointment of Tribunes of the Plebs, with power of administrative veto.