The Knights of St John built this fortification in the 15th century to guard the entrance to the harbour at a time when Kos was in the sights of the Ottoman Empire.
The castle has two layers of walls, the innermost being older and dating to the mid-15th century, while the outer wall is from the turn of the 16th century.
After Kos was captured by the Ottomans in the 1500s the castle was a garrison and the seat of the island’s commander.
