Athanasiy Velyki, O.S.B.M., was born on November 5, 1918, in Turynka, Zhovkva county, Galicia.
He also studied the history of the Eastern church at the Pontifical Oriental Institute (1946–8) and palaeography at the Vatican.
From 1960 to 1965 Velyki served as president of the Ukrainian Theological Scholarly Society and secretary of the Vatican's Preconciliar and Conciliar Commission on the Eastern Churches.
He also wrote a history of the Sisters Servants of Mary Immaculate (1968), Svitla i tini (Lights and Shadows, 1969), Ukraïns'ke khrystyianstvo (Ukrainian Christianity, 1969), and Z litopysu khrystyians'koï Ukraïny (From the Chronicle of Christian Ukraine, 9 vols, 1968–77).
He contributed many entries to Entsyklopediia ukraïnoznavstva and Encyclopedia of Ukraine and drafted the missive from the Ukrainian Catholic church hierarchy on the anniversary of Saint Olha and the official statement issued by the Ukrainian bishops regarding the release from Siberia of Metropolitan Josyf Slipyj.