The imposing bastion wall was built over the course of fifteen years (1525-1540) to meet a twofold need:
1 - to protect the upper city with an apparatus of 'modern' fortifications suitable for the use of firearms and close flanking defence;
2 - to give, from the cannon positions in the upper city, the widest possible cover to the naval landing places below..
For the construction of the enclosure, Viceroy Ettore Pignatelli called upon the work of Pietro Antonio Tomasello, 'magistro ingigneri' of the city of Padua, who had already been entrusted with the task of ascertaining the efficiency of the defence of the port cities. In the Milazzese construction site, which started in February 1525, Tomasello chose to build the new defences on the traces of the medieval ones that still existed for the most part, but were now inadequate. Starting in 1553, the Paduan technician, who was old and in ill health, was joined by a technician from a similar but more up-to-date school, Antonio Ferramolino from Bergamo.
The constraints imposed by the ancient structures along the entire front and at the sites of the two gates, St. Mary's and the Annunziata, ended up ticking off the more innovative intentions of the two technicians of the Veneto-Lombard school. The long construction times also made the technical choices made less linear and coherent. One example for all: the presence of the 55 machicolations arranged on the long wall, according to the antiquated schemes of the piombante defence, hardly reconciles with the adoption of the gun ports facing each other in the ravines ("orecchioni") of the two bastions and placed to protect the same front. Thus it is probable that the first engineer was responsible for the choice of machicolations and the plumbant defence, while the second was responsible for the choice of embrasures, protective "ears" and flanking defence.
Terranova C. P., La città murata. Dalla visita al "memorabile viaggio.", in Milazzo Nostra n. 28-29 - Marzo-Luglio 2011, p. 21.