He was monk and theologian, who served as the Archibishop of Athens and All Greece and as the primate of the Autocephalous Orthodox Church of Greece  in 1967–1973, during the military junta of 1967-1974. He is considered among the most important 20th century theologians in Greece.

He studied at the Rizareios Ecclesiatical School  and continued his studies at the Theological Faculty of the University of Athen . After graduation, he went for further studies to Germany (in Munich, Berlin and Bonn) and Britain. 

Through his spiritual father's influence, Archimandrite Seraphim Papakostas, he became a protégé of the then-Archbishop of Athens, Chrysanthus. As a close associate of Chrysanthus, he was dismissed from his secretary to the Holy Synod by the collaborationist government during the Axis Occupation of Greece, and spent the Occupation as chaplain of the Evaggelismos Hospital. After the occupation, he submitted a dissertation for a position of lecturer at the Theological Faculty, but later withdrew it after quarrelling with his teachers. On 29 September 1949 he was appointed head priest of the Royal Palace. Finally in 1959, he was elected as Professor of Canon Law in the Aristotle University of Athens.