The village Kastro of Sifnos is on a rock at the eastern coast of the island and was its capital from antiquity until 1836.

It is a characteristic medieval fortified settlement of the Aegean, where the walls of the houses are part of the fortified perimeter.

There is no castle preserved as a whole there, but there are many elements of the fortification scattered in the modern settlement, such as parts of the walls, the logias (small tunel-like gates) etc. There are also many spolia from the ancient period embedded in relatively recent buildings.

History

After the fall of Constantinople in 1204, Sifnos, like the rest of the Cyclades, became part of the Duchy of Naxos since 1207, under the Venetian Marco Sanudo.

In 1269 Sifnos was recaptured by the Byzantines, but in 1307 it came under the power of the Italian or Spanish Hospitaller (knight of the Order of St John) Januli I da Corogna, who proclaimed himself an independent ruler. The Corognas ruled Sifnos for over a hundred years; Around 1456 as a result of a dynastic marriage, power over the island passed to a Bolognese family, the Gozzadini, who ruled until 1617. Though both these dynasties became thoroughly Hellenized, they retained their Roman Catholic religion.

The “castle” Was first developed in the period of Corognas (14th century) and was further improved in the next centuries in the Gozzadini era.