He was responsible for the repression of several indigenous nations in Bahia and especially Piauí, which he is reputed to have been the first colonist to explore.

His greater fame, however, is due to his conquest of the Quilombo dos Palmares, in the hinterland of Alagoas, on behalf of João da Cunha Souto Maior, governor of Pernambuco.

Velho accepted the assignment and, in 1694, with an army of amerindians and mamelucos, European Native American offspring, overran the fortified city of Macacos, on the Serra da Barriga mountain.

[1] According to the bishop of Olinda at the time, he did not speak Portuguese fluently but rather the língua geral, a lingua franca based on Tupian languages spoken in Brazil at that time.

[2] John Manuel Monteiro, a specialist on the subject, in Os Negros da Terra, explains that Velho not only spoke Portuguese but was indeed literate: "actually Domingos not only spoke but he also wrote in Portuguese, what would be highly unusual for a Tapuia [...] Domingos even wrote a letter to the Portuguese King, and his recognizable signature can be identified frequently in the civil registries of Santana de Parnaíba".