The castles formed a defensive triangle, with Gardiki guarding the island's south, Kassiopi the northeast and Angelokastro the northwest.

[7] In 1084 the fortress fell into the hands of Alexios I Komnenos after he defeated the Norman fleet following three naval battles in the Corfu Channel.

[5] Dona went in situ to Kassiopi to evaluate the castle and its prospects of defending Corfu from the Ottomans who were planning an invasion of the island from Epirus.

Based on further advice by general St. Andrea and military engineer Verneda, Dona's report to the Venetian Senate supported the strengthening of the Kassiopi Fortress.

The genesis of these myths is attributed to the impression the use of black powder and explosions made to the area residents who were unfamiliar with these advances in military warfare.

[5] Following the second great siege of Corfu in 1716, the Venetians finally decided to rebuild the castle, although the local population had already moved to other places including villages on the highlands of Mount Pantokrator.

[8] The perimeter of the castle has a length of 1.073 km and is of a quadrilateral shape with 19 strong towers of alternating circular and rectangular cross sections guarding the walls and runs in the southwest to northeast direction.

[5] Since the walls of the castle are vertical, and not inclined so that cannon projectiles could bounce off them, the design was meant to repulse conventional siege machinery developed prior to the advent of artillery.

Access to the fortress is mainly from the southeast through a narrow walkway which includes passage from homes and backyards, since the castle is at the centre of the densely built area of the small village of Kassiopi.