In 1574 the first extension was undertaken, with the construction of two bastions, although prior to that a wall was built, of which the ancient gate still remains that can be seen built into the current wall. It did not take on its current appearance until the 18th century.
A tower was built in the centre of the complex, with the marble-framed gate to the city at its base. On the façade facing the historical centre, a marble portico was constructed in the shape of a triumphal arch, with overtones that are rather more religious than military. On both sides of the walls we can see the bastions of San Roque and Santa Elena, so named because they face two nearby chapels that were demolished in the 18th century to make way for the barracks built inside the complex.