cabildo (käbēl´dō), autonomous municipal council, the lowest administrative unit in the Spanish government. The institution was especially influential in Spanish America, where it was set up in the early 16th cent. in imitation of the Castilian ayuntamiento, the name it was at first briefly called. Composed originally of elected administrative officials, usually local landowners, it was the only institution in which creoles could participate. It was presided over by the alcalde mayor, the administrator of a provincial division, who was assisted in judicial matters by alcaldes ordinarios (see alcalde). The cabildo exercised considerable executive, legislative, and judicial powers; it distributed lands, imposed taxes, provided for police service, and supervised trade and public facilities such as hospitals and jails. In case of emergency the council could choose a governor, lieutenant governor, or captain general. The cabildo steadily evolved in the course of the 16th and 17th cent. into an appointive, proprietary, and hereditary body of generally 4 to 12 councilors. Corruption and inefficiency became common. The degree of local autonomy at first granted by the crown was soon hedged in by the increasing centralization of power in higher authorities, such as the audiencia and viceroyalty. The cabildo regained importance during the independence movement of the early 19th cent. As the only self-perpetuating organ of local self-government with an ancient tradition of civil autonomy, it served as a convenient rallying place for voicing nationalistic ideas.