Diego Gómez de Ocampo in the style of the French military architect Sébastien Le Prestre de Vauban. The modified design was implemented in 1689. Three bastions were functioning by 1697 (Nuestra Señora de Concepción, Nuestra Señora de Regla and the San Felipe Keep).
Additional fortifications were designed by engineer José Sierra and added in 1797; they included three artillery batteries known as the batteries of San Carlos, San Felipe and Santiago. Two barracks were also added (Buenavista and Santiago)
