The Old Venetian Fortress of Corfu covers the promontory which initially contained the old town of Corfu that had emerged during Byzantine times.
Before the Venetian era the promontory, which lies between the Gulf of Kerkyra to the north and Garitsa Bay to the south, was defended by Byzantine fortifications which the Venetians largely replaced with fortifications of their own design. As part of their defensive plans the Venetians separated the promontory from the rest of the city of Corfu by creating the Contrafossa, a moat which is a sea channel connecting the Gulf of Kerkyra to the North with the Bay of Garitsa to the South, converting the citadel into an artificial island.
The fort successfully repulsed all three major Ottoman sieges: the great siege of 1537, the siege of 1571 and the second great siege of Corfu in 1716.
In 1718 lightning struck the powder magazine at Castel da Mare causing an explosion which created a chain reaction during which three secondary ammunition facilities also exploded, this in turn destroying most buildings inside the castle including the palace of the Captain General of the fortress, and many city buildings. Commander of the fortress and hundreds of others died in the explosion.
The fortress houses today the Public library of Corfu which is located in the old British barracks. The fortress grounds are also used for various types of art and culture exhibits. The Hellenic Music Research Lab of the Ionian University is also located at the Old Fortress.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.