When the Eritrean Orthodox Tewahedo Church sought autocephaly, he was one of five abbots of monasteries that went to Egypt to be ordained as bishops so that the church would have its own Holy Synod. He was ordained as Bishop Antonios of Hamasien-Asmara on 19 June 1994 in Saint Mark's Coptic Orthodox Cathedral, Cairo, by Shenouda III, Pope of the Coptic Orthodox Church of Alexandria. Following the death of Abune Yacob in 2003, he was elected Patriarch in popular elections which were unanimously endorsed by the Holy Synod of the church.