Patmos (Greek, πάτμος; Italian: Patmo) is a small Greek island in the Aegean Sea. One of the northernmost islands of the Dodecanese complex,) it has a population of 2,998 and an area of 34.05 km 2 (13.15 sq mi).The highest point is Profitis Ilias, 269 metres (883 ft) above sea level.he churches and communities on Patmos are of the Eastern Orthodox tradition. In 1999, the island's historic center Chora, along with the Monastery of Saint John the Theologian and the Cave of the Apocalypse, were declared World Heritage Sites by UNESCO. The monastery was founded by Saint Christodulos.