 Although Mariano Moreno was a criollo , a Spanish citizen born in the Americas , he did not work with the other criollos of Buenos Aires who sought to promote political changes against the privileges of the Spanish @-@ born . Unlike the criollo politicians Manuel Belgrano and Juan José Castelli , he did not support viceroy Liniers or the Carlotist project , which sought the coronation of Carlota of Spain in the Americas . He joined mayor Martín de Álzaga instead , which allowed him to serve as legal adviser of the Cabildo . In that capacity , he wrote a petition to the King of Spain , so that the Buenos Aires Cabildo was named Protector of the Cabildos of the Viceroyalty of the Río de la Plata . As a result , all petitions from local cabildos to the King or the Viceroy would be channeled through the Cabildo at the capital . 
