The town and fortress were founded in 583 by inhabitants of the mainland seeking refuge from the Slavic and the Avaric invasion of Greece.
It remained part of the Byzantine Empire until 1460, becoming the seat of an imperial governor, a landing place for Byzantine operations against the Franks, the main port of shipment (if not always production) for Malmsey wine, and one of the most dangerous lairs of corsairs in the Levant.