Dayro d-Mor Gabriel (the Monastery of Saint Gabriel), also known as Deyrulumur,is the oldest surviving Syriac Orthodox monastery in the world,located on the Tur Abdin plateau near Midyat in the Mardin Province in southeastern Turkey.was founded in 397 by the ascetic Mor Shmu'el (Samuel)and his student Mor Shem'un (Simon).The monastery became so famous that it received contributions from Roman Emperors,such as Arcadius,Honorius,Theodosius II and Anastasius.