prior to napoleon's threats, the firepower of the fortress was increased. at that time, rio was the main point of embarkation for the nearby gold and diamond mining operations, in the neighboring state of minas gerais, for the shipment to lisbon.

combined with the other forts guarding the port such as the forte do são joão and the forte são luiz, this fortress formed an excellent defensive network for rio de janeiro and for guanabara bay.