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.
He was consecrated in September, 885, without waiting for the imperial confirmation; but when Charles the Fat found with what unanimity he had been elected he let the matter rest.
Stephen was called upon to face a famine caused by a drought and by locusts, and as the papal treasury was empty he had to fall back on his father's wealth to relieve the poor, to redeem captives, and to repair churches.
To promote order he adopted Guy III of Spoleto "as his son" and crowned him Emperor (891). He also recognized Louis the Blind as King of Provence. As Aurelian, Archbishop of Lyon, would not consecrate Teutbold who had been canonically elected Bishop of Langres, Stephen himself consecrated him. He had also to oppose the arbitrary proceedings of the Archbishops of Bordeaux and Ravenna, and to resist the attacks which the Patriarch Photius made on the Holy See. His resistance was successful, and the Emperor Leo Sent the disturber into exile. When writing against Photius, he begged the emperor to send warships and soldiers to enable him to ward off the assaults of the Saracens.