St Dometius lived in Persia during the fourth century. In his youth he was converted to the Faith by a Christian named Uaros. Forsaking Persia, he withdrew to the frontier city of Nisibis (in Mesopotamia), where he was baptized in one of the monasteries, and also received the monastic tonsure.
Fleeing the ill-will of some of the monks, St Dometius moved to the monastery of Saints Sergius and Bacchus in the city of Theodosiopolis. The monastery was under the guidance of an archimandrite named Urbelos, a strict ascetic, of whom it was said that for sixty years he did not taste cooked food, nor did he lay down for sleep, but rather took his rest standing up, supporting himself upon his staff.
In this monastery St Dometius was ordained a deacon, but when the archimandrite decided to have him made a presbyter, the saint, considering himself unworthy, hid himself on a desolate mountain in Syria, in the region of Cyrrhus.
Stories about him constantly spread among the local inhabitants. They began to come to him for healing and for help. Many pagans were brought to faith in Christ by Dometius. And one time, in the locality where St Dometius struggled with his disciples, the emperor Julian the Apostate (361-363) arrived, traveling on his campaign against the Persians. By order of the emperor, soldiers found St Dometius praying with his disciples in a cave, and walled them up alive inside.