He demonstrated an early interest in politics. He became a provincial "cabildo" member in 1807, fiscal officer in 1808 and attained with difficulty the position of "alcalde del primer voto", or head of the Asunción "cabildo", by August 1809, the highest position he could aspire to as a "criollo". He had tried in 1798 but failed because of his humble background. Other significant members included Fulgencio Yegros; Pedro Juan Caballero; Manuel Atanasio Cabañas; and the last colonial governor, Bernardo de Velasco.