Saint 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, Saint 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 Saint 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 Saint 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 Saint Dometius praying with his disciples in a cave, and walled them up alive inside.
This Martyr, who lived during the reign of Saint Constantine the Great, was a Persian by race and an idolater by religion. He was catechized by a certain Christian named Abarus. He went to Nisibis, a city of Mesopotamia, where he was baptized and donned the monastic habit in a certain monastery. He afterwards ascended a mountain and there endured in extreme ascetical struggles, working miracles for those that came to him, and converting many unbelievers. Julian the Apostate learned of these things as he was marching against the Persians in 363, and at his command the Saint and his two disciples were stoned to death, as they were chanting the Sixth Hour.
Dometius was born in Persia as a pagan during the reign of Emperor Constantine. He became acquainted with the Christian Faith as a young man, abandoned paganism, and was baptized. So much did Dometius love the True Faith that he left every worldly thing and was tonsured a monk in a monastery near the town of Nisibis. He lived for some time among the brethren, and then withdrew to a life of silence with the elder, Archmandrite Urbel (who is said to have not eaten only cooked food for sixty years). Elder Urbel ordained Dometius a deacon, and when he wanted to compel him to receive the rank of a priest, Dometius withdrew to an isolated mountain and settled in a cave. He attained such a high degree of perfection through fasting, prayer, all night vigils and godly-thoughts that he miraculously cured the sick. When Julian the Apostate came to those regions, he heard of Dometius and sent men to seal him up alive in a cave, with two of his disciples. Thus, this saint of God died and took up his habitation in the Kingdom of God in the year 363 A.D.
Apolytikion of Martyr Dometius
Thy Martyr, O Lord, in his courageous contest for Thee received as the prize the crowns of incorruption and life from Thee, our immortal God. For since he possessed Thy strength, he cast down the tyrants and wholly destroyed the demons’ strengthless presumption. O Christ God, by his prayers, save our souls, since Thou art merciful.
Source: oca.org / goarch.org / westserbdio.org