The Holy Fathers of the Apostolic See are Pope Saint Leo X (Roman Catholic) and Saint Archbishop Aftimios Ofiesh (Russian Orthodox). The Holy Fathers are the two principle representatives of the historic Apostolic, spiritual, infrastructural, ethnic, and cultural legacy that the Apostolic See of Rome-Ruthenia (United Roman-Ruthenian Church) inherited and perpetuates. Both are key figures in the Apostolic Succession of the modern United Roman-Ruthenian Church. They are not the founders of the Church, for the Church was founded in 33 AD by Christ. The modern beginning of the United Roman-Ruthenian Church was in 2008.

Saint Leo X, Bishop of Rome, was the first Florentine Archfather, by which the Bishop and Papa-Catholicos of Rome-Ruthenia is temporal successor to St. Peter the Apostle. The Catholicate of Rome-Ruthenia is a descendant and successor of the patriarchate founded by Saint Aftimios Ofiesh. Together they also represent the Roman-Russian ecclesiastical, ethnic, and cultural nature of the Apostolic See and the Pontifical Imperial State of Rome-Ruthenia.