Why go
Corfu's position at the Adriatic entrance made it a prize for Byzantine, Norman and Italian powers. Venice later strengthened the island's defences against Ottoman attacks; the Old and New Fortresses and older island castles make those pressures visible. Compare town defences with the castles farther across the island.
The full story
Corfu changed hands repeatedly in the medieval centuries. Byzantine control was challenged by Norman rulers from Sicily and by other powers competing across the Ionian Sea. Venetian influence grew from the late fourteenth century, and the republic held the island until 1797. Its long rule shaped both the town's streets and a defensive network across the island. The Old and New Fortresses in Corfu Town frame the capital, while older positions such as Angelokastro, Kassiopi Castle and Gardiki show that defence extended far beyond it. Ottoman attacks and sieges repeatedly tested those works, notably in 1716. Rather than reading the fortresses as isolated scenic viewpoints, compare their locations and sightlines: each was built to control an approach or protect a settlement. The surviving structures also explain why the capital developed as a dense fortified town. A castle visit adds meaning to the wider landscape, and the Old Town walk shows what grew within the protection of its walls.