The Monastery of the evangelist St John the Divine sits on top of a prominent cliff bluff and can be seen from virtually everywhere on the island. The monastery's high grey walls are fringed the white cube houses of Chora. It looks more fortress than monastery and that was part of its purpose, to keep monks and villagers safe from attacks by marauding pirates.
That is also the reason why, despite its large size, it has only two doors in its 15m high walls. There is even a balcony from which molten lead could be poured down an any attackers trying to storm the main gate.
Building began in 1088 under the direction of the monk Hosios Christodoulos. The interior is a multi-levelled complex with interior courtyards, colonnades and narrow corridors.
Inside, the visitor first enters the cobbled courtyard lined with four chapels. To the north the monk's cells are constructed around the main nave or catholikon, in the Byzantine style and an astonishing temple constructed in 1820 by 12 craftsmen and containing the abbot's chair and many beautiful icons.
Indeed many of the monastery's icons are beyond price, as indeed are many of the treasures inside, especially the sacristy, built by the bishop Nikiforos of Laodicia with a large icon of the revelation, dating from 1625, and an 11th century icon of Agios Nikolaos, as well as jewels, gold and silverware donated by rich Patmians.
The historic library is considered today one of the most important religious libraries in Greece, if not the whole Christian world, with 900 rare manuscripts from the 15th and 16th centuries, more than 20,000 rare books and around 13,000 other manuscripts and codes.