In 1088 Christodoulos, a Bithynian monk, persuaded Emperor Alexis to grant him the island of Patmos, at the northern end of the Dodecanese group, to found a monastery.
The monastery was built on higher ground for security reasons and resembles a castle rather than a home for monks. Perhaps for that reason the monastery has never been plundered. Its library is rich in treasures, and the treasury itself has some splendid mediaeval vestments and textiles.
The monastery has ten chapels, four in the main courtyard, which date back to 1698. The entrance dates back to 1738.
The monastery is one of the few places in the world where religious ceremonies dating back to early Christian times are still being practised unchanged.
The monastery of St. John the Theologian is a World Heritage Site