Apano Kastro, Naxos

Apano Kastro of Naxos is a medieval fortress in the municipality of Naxos, Greece, originally built and developed under Byzantine control.

In antiquity the hill was recognized for its strategic position at the island’s center. During the Byzantine period the site was rebuilt to protect the fertile Tragaia valley from Saracen pirate raids. The Byzantines equipped the castle with cisterns and storerooms so defenders could hold out during protracted sieges.

After the Venetians established control of the Cyclades, a traditional account credits Marco Sanudo, Duke of Naxos, with giving the castle its lasting appearance sometime after about 1207. Recent archaeological work challenges that dating and indicates that the fortress reached its final medieval form later, toward the early 1300s.

Around 1390, in response to the growing Ottoman naval threat following raids by the fleet of Bayezid I, substantial rebuilding was carried out. New curtain walls and artillery-adapted defenses were added, including circular towers equipped with gunports for cannon. Around 1500, during a brief period of direct Venetian administration under Duke Francesco III Crispo, further works strengthened the south flank by adding new wall lines and two circular bastions that are reported to survive.

The castle endured repeated attacks over the centuries but seldom surrendered. Hayreddin Barbarossa failed to take it in 1537, while the corsair Hugues de Crevelliers captured the site only briefly in 1678. Archaeological investigation of the monument’s building phases has led to revisions of the traditional narrative attributing its definitive shape to Sanudo, showing significant construction activity after his era.