The main attraction of Chora is the Monastery of Saint John the Theologian, which is located above the houses of the capital. It was built in 1088 in the form of a castle by Saint Christodoulos, in order to protect the island from pirates. After the siege of Constantinople in 1453, many Byzantine families relocated to Patmos and built the settlement of Allotina next to the monastery.
To this day this monastery is inhabited by a good number of monks, and belongs to the Patriarchate of Constantinople which possesses huge land holdings in Greece and abroad. Apart from a well-fortified castle, the monastery is also a center of intellectual study. The monastery’s famous library housed nearby has a collection of around 1000 manuscripts, papyri that can only be seen in the Monastery of Sina, and over 3000 books. In the vestry there are impressive paintings, icons and mosaics such as the mosaic of Agios Nikolaos that dates back to the Byzantine period (11^th century).