The castle of Chysocheria was the headquarters of the Hospitaller castellan, the island's governor. The castle's defences were put to the test in 1457 when the island, together with the islands of Nisyro, Lerro, Piskopi and the castle of Archangelus on Rhodes were subjected to large-scale Turkish raids. Further significant raids followed in 1460. The castle eventually surrendered to the Turks in 1522.
The castle takes its present name Chysochera, from a hoard of gold coins that were discovered under the church of Panagia Chrysocheria (Virgin of the Golden Hands) within the castle walls. The other church within the walls of Chrysocheria is dedicated to St. George.