Apaliros Castle

Apaliros Castle stands on a steep hill in the interior of Naxos, between the villages of Sagri and Agiassos. Although no founding document survives, pottery and coins suggest the site was occupied before the seventh century, with the fortifications likely raised in the early years of Leo III (717-741). It served as the acropolis of Byzantine Naxos until 1207, when Marco Sanudo besieged it for forty days following the Fourth Crusade. Its fall marked the beginning of Venetian rule over the Cyclades, lasting until 1537. Sanudo then built his own castle by the sea at Chora, and Apaliros was abandoned, possibly demolished on his orders to deny its use to rivals.

The castle covers 20,000 square metres with a perimeter of 745 metres, laid out along a north-south axis. Much of the wall survives, with towers, bastions, and the remains of some 250 houses, churches, a bakery and an olive mill. Its most distinctive feature is the cisterns: five large communal tanks and 52 private ones built into house basements, reflecting the absence of natural springs and a sophisticated system of rainwater collection.