The bastion of the islands was planned by the military engineer Pietro
Antonio Tomasello. Its construction was assigned, in April 1529, to the
master-builder Carlo Florio, with 9 skilled workers and 22 labourers. A further
24 labourers were also involved in the preliminary excavations for the
construction of the foundations that were completed by October 1529.
This bastion includes an entrance portico and 4 large areas, of which
only 3 are currently accessible. Beyond the portico, built subsequently to the
bastion, a ramp of stone steps leads into the first area where there are the
remains of a cannon emplacement and a stone fountain fed from a cistern that
can be seen from the terraces of the bastion.
A small opening beside the fountain leads into the second area with a
robust barrel vault ceiling, strong enough to take the weight of the artillery
positioned on the terraces above. Other cannons would have fired from the 3 lower
cannon emplacements in this second area, the walls of which were reinforced
with 3 long steps used to block enemy cannon fire. These 3 cannon emplacements
were walled up a few decades ago but it is possible to observe them from the
interior of the bastion through 5 apertures. One aperture in the centre of the
barrel vault ceiling provided illumination and at one time also served as a
vent for the release of smoke produced by cannon fire. An iron gate opens onto
a steep stone staircase that leads down to the dark, gloomy tunnel within the
foundations of the bastion.
A visit to the bastion, which was completed in around 1537, ends in a
third large room, which, until restoration work carried out in 2010, was entirely
full of earth. A walled arch hides a fourth and final area, which is still full
of earth and that contains a further cannon emplacement.
The portico leading into the interior
Within the foundations
of the bastion a long, dark tunnel (“contromina”, countermine) used to defend
the bastion from the enemy using underground tunnels (known as “mines”). Ducts
known as catùsi opened from the
ceiling of the tunnel. Asphyxiating substances would be poured into these ducts
onto the enemy if they had managed to break into the tunnel.
