The most important cultural and religious center of the island of Patmos is a Greek Orthodox monastery St. John the theologian. Grand structure stands on a picturesque hill in the island's capital, Chora.

The monastery was founded in 1088 by St. Christodoulos with the permission of the Byzantine Emperor Alexius I Comnenus. Externally, the monastery has a view of the majestic fortifications with massive battlements, towers and bastions. Such protective measures have been taken not by chance, as in this historical period there was the constant threat of pirate raids and a greater likelihood of attack by Turkish invaders. The monastery was built on the ruins of the ancient temple of Artemis, and the fragments of an ancient sanctuary was used in the construction of the monastery walls and some internal structures. The monk Christodoulos and became the first Abbot of the monastery.

A large part of the monastery complex was completed in three years, although overall construction lasted almost 20 years, and some buildings were completely built several centuries later. Today the monastery is the main Church room (with a magnificent iconostasis and beautiful frescoes), ten chapels, and many administrative buildings. In one of the chapels contains the relics of the monk Christodoulos.

Of special interest is the magnificent monastery library (one of the largest Christian libraries in the world), which holds rare books, including incunabula, unique manuscripts, valuable historical documents, etc. but the Main relic of the library is considered a gold bull or Chrysobull of Alexios I Comnenus, which launched the history of the monastery. Not less interesting Ecclesiastical Museum (Treasury). In his exposition presents unique icons, Church utensils, gorgeous vestments, embroidered with gold and silver threads and decorated with precious stones and other sacred relics.

The monastery of Saint John the theologian is highly revered in the religious world, both Orthodox and Catholics. This magnificent historical monument included in the world heritage list of UNESCO. Every year it is visited by a huge number of people from all over the world.