Pope Stephen V, (885-891), succeeded Pope Adrian III, and was in turn succeeded by Pope Formosus. In his dealings with Constantinople in the matter of Photius, as also in his relations with the young Slavonic church, he pursued the policy of Pope Nicholas I. His father, Hadrian, who belonged to the Roman aristocracy, entrusted his education to his relative, Bishop Zachary, librarian of the Holy See. Stephen was created cardinal-priest of SS. Quattro Coronati by Marinus I, and his obvious holiness was the cause of his being chosen pope.