Mount Galesios or Galesion (Greek: όρος Γαλήσιος/Γαλήσιον), today known as Alamandağ or Gallesion in Turkish,[2] is a mountain north of Ephesus in modern-day Turkey.

The mountain is located on the northern bank of the Küçükmenderes River (ancient Kaystros), on the western coast of Asia Minor.

[3] The first monastic community on the mountain was established by the stylite monk Lazaros of Mount Galesios, who died there in 1053.

[3] A fourth monastery, the Theotokos of Bessai, was established by the imperial family and housed up to 300 monks, but it rapidly declined after the 11th century.

[3] The death of Lazaros deprived the community of much of its prestige, but it re-emerged into prominence in the 13th century, with the establishment of the Empire of Nicaea,[3] when the neighbouring city of Nymphaion became the favourite winter residence of the Nicaean emperors.