The future Patriarch was born on 12 July 1927 in the town of Hembrti, to the north of Asmara in the province of Hamisien. His father, Ghabre-Medhin Debre Sion was a priest and his mother was called Ellen Keleta. At the age of five he was sent to the monastery of Debre Tsege Abuna Andrewes where he was educated for the service of the church, being ordained a deacon when he was twelve. Professed as a monk and ordained priest as Abba Yemane-Berhan in 1942, he was elected Abbot in 1955.
His exemplary life and strong leadership enabled him to improve and to reconstruct the daily life and education standards in the monastery, for both the monks and its students, showing openness to new ideas in education, technology and medicine. He is remembered for his immense contribution to the development and expansion of the monastery. His care and support for the sick: those suffering from leprosy, depression and other illnesses, showed a deeply pastoral spirit. He is loved and respected for his religious devotion, theological scholarship and independence. Personally devout, polite, thoughtful and respectful to the young, many Sunday-School students in Asmara describe him as gracious, considerate, genteel, friendly and sociable.
When the Eritrean Orthodox Tewhado Church first sought its independence, he was one of the five abbots of monasteries to be sent to Egypt as bishops-elect in preparation for their Episcopal ordination so that the newly independent church would have its own Holy Synod. On the Feast of Pentecost, 19 June 1994 in St. Mark’s Cathedral, Cairo, he was ordained as Bishops Antonios of Hamasien-Asmara in a ceremony presided over by His Holiness Shenouda III, Pope and Patriarch of Alexandria, assisted by the Metropolitans and Bishops of the Coptic Orthodox Church.
Following the death in 2003 of Abune Yacoub, second Patriarch of the Eritrean Church, he received the highest share of votes in Popular Formal Elections for the Patriarchate held on 2 March 2006 and was unanimously elected Patriarch by the Holy Synod on 5 March. His solemn ordination and enthronement as Patriarch took place on 23 April in the Holy Virgin Cathedral in Asmara, at the hands of Pope Shenouda III, assisted by Eritrean and Coptic Orthodox Metropolitans and Bishops.