Assos Castle

Assos Castle was raised because Kefalonia's existing stronghold, St George's Castle, could no longer be trusted to defend the whole island against Ottoman raids and piracy. In 1584 the island's nobles petitioned the Venetian Senate for a new fortress, and Venice, which planned to found a town within its walls and shift its island administration there from St George's, began building in 1593 under the supervision of Ambrosius Cornelius. The castle itself was designed by the Venetian architect Marino Gentillini and completed by 1596, its walls running some 2,000 metres around a hilltop 170 metres above the sea, taking in the whole of the Assos peninsula and overlooking the bay of Agia Kyriaki north of Paliki. Gentillini married and settled on Kefalonia, was recorded in the Venetian nobility's Libro d'Oro, and his descendants still run the island's Gentillini winery.

Assos itself never held more than a small population: its position meant that under siege its supplies, water included, could be cut off. Even so, the fortress became the administrative capital of northern Kefalonia, a large defensive circuit around a modest settlement. Its strategic value fell away in 1684, once Venice took Lefkada from the Ottomans, and by 1757, with piracy and the Turkish threat both reduced, the Venetians founded Argostoli as the island's new main town. Assos nonetheless remained the seat of the Venetian provveditore until the fall of the Republic of Venice ended Venetian rule over Kefalonia in 1797.

In 1822 refugees from Souli arrived to shelter within the fortress — put at about 1,700 by one account, 7,000 by another — and the site was made a quarantine area, giving its name to a settlement, Souli, inside the walls. For the following century Assos carried on as a fortress with no military function. A prison opened there in the late 1920s and, after the Second World War, held political prisoners who worked vineyards and grew cereals inside the walls. The 1953 Ionian earthquake badly damaged the islands; most of the castle's remaining residents left afterwards and the prison closed. The 1961 census counted only six people still living inside the walls, and the last of them left in 1963 — families who had cultivated olives and grapes there and were known locally as the "Kastrinoi".

Alongside St George's Castle, it is a fine example of the island's military architecture; the British general Charles James Napier described it as "stronger than Gibraltar". The ruins of a Venetian building belonging to the Gentillini family stand near the church inside the walls. The site is designated an archaeological site and a protected building in Greece, and is open daily with no entry fee, reached along a renovated stone path; an arched gate bearing the Venetian Lion of Saint Mark and sections of the walls survive, along with the small church of St Mark and the former house of the Venetian high commissioner.