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.