A cabildo (Spanish pronunciation: [kaˈβildo]) or ayuntamiento (Spanish: [aʝuntaˈmjento]) was a Spanish colonial, and early post-colonial, administrative council which governed a municipality. Cabildos were sometimes appointed, sometimes elected; but they were considered to be representative of all land-owning heads of household (vecinos). The colonial cabildo was essentially the same as the one developed in medieval Castile.
The cabildo was the legal representative of the municipality—and its vecinos—before the Crown, therefore it was among the first institutions established by the conquistadors themselves after, or even before, taking over an area. For example, Hernán Cortés established La Villa Rica de la Vera Cruz to free himself from the authority of the Governor of Cuba.
The word cabildo has the same Latin root (capitulum) as the English word chapter, and in fact, is also the Spanish word for a cathedral chapter. Historically the term ayuntamiento was often preceded by the word excelentísimo (English: "most excellent") as a style of office, when referring to the council. This phrase is often abbreviated Exc.mo Ay.to