During the persecution of Christians under Emperor Diocletian, he traveled as a bishop from Italy to Soreos in Bithynia (Asia Minor). There, he converted many to Christianity and built a church dedicated to the Holy Archangel Michael. He lived in the home of a Christian named Cornelius, whom he ordained first as a presbyter and later as a bishop. Saint Autonomus subsequently went to the nearby town of Limna—inhabited exclusively by pagans—and enlightened many with the Gospel. This enraged the pagans; one day, they stormed the Church of the Holy Archangel Michael during the divine service and killed Saint Autonomus within the altar, along with many Christians inside the church itself. During the reign of Emperor Constantine, a nobleman named Severian erected a church over the grave of Saint Autonomus. His relics are incorrupt and wonder-working.

Hieromartyr Cornutus, Bishop of Iconium. Saint Martyr Julian with forty companions. Venerable Daniel of Thasos. Holy Martyrs Macedonius, Tatian, and Theodulus.