The islet and the fortress of Spinalonga in a design by Francesco Basilicata (1618). © "Micros Nautilus" Publications - Vikelaia Library – Local Union of Municipalities and Communities of Crete

The construction phases

The complex of fortifications, as preserved today, results from several construction phases. Construction begins in June 1579. According to the proposal of the Venetian engineer Genese Bressani, a perimeter coastal enclosure is built, reinforced at crucial points with bastions and fortifications are formed on the highest points of the north and south sides to exclude any possibility of enemy landing on the island's territory.

The Bressani plan is not finished, as it is considered inadequate by the Cretan military commander Latino Orsini, who visits the islet in 1584 and proposes the construction of another line of defense on the ridge to secure the fortifications of the lower enclosure and reduce the overall construction cost, as much of the remaining lower zone work envisaged by the Bressani plan could now be omitted. In 1585, construction work of the fortifications begins on the ridge above the ruins of the old fortification. However, after 1586, the financial difficulties of the Venetian Republic forces the limitation of the works, and gradually, the interest in Spinalonga decreases.

The islet comes to the fore again at the beginning of the 17th century, especially after the Ottoman invasion of Crete in 1645. The Venetians carry out a series of extensive modifications and changes, making serious efforts to strengthen the fortifications. Specifically, during the Cretan War (1645-1669), extensive work is done on virtually the entire perimeter fortification. The walls rise, while in the specific fortifications, canon openings are constructed. This period's constructions are less elaborate than those of the earlier phase, as the construction works are done under challenging conditions, in wartime, with limited financial resources and supply difficulties.