Historic patriarchal monastery in a picturesque valley of the mountain. It was established in 1522 by Saint Theonas, Metropolitan Bishop of Thessaloniki, on the position of an older church, probably belonging to the monastery of Chortaitos which is said to have been founded by Emperor Leon VI, The Wise, in the 9th century. Traces of a prehistoric settlement were found in the same position. Tradition has it that the monastery was founded by Anastasia, daughter of a rich Roman and the Christian Fausta. Christians made her a saint and called her Pharmakolytria (Deliverer from Potions), because among her numerous miracles, she could heal from the ill effects of spells, potions, poisons and other harmful substances. The monastery had many dependencies in Halkidiki with significant yield. The Turks burned it down many times, while almost all of its present buildings were constructed after the big fire of 1821. The impressive south wing of the monastery with the paratholia in its interior, has been extant since Theonas’ times. The country churches of Saint Theonas, Agios Kirykos and Ioulitis, Agia Triada, and Prophet Elias are also quite impressive. The first was probably the place Saint Theonas was an ascetic. The second, which is found on the position of the important prehistoric settlement, was painted around 1830 by icon painters from Galatista.