PHOTIOS (c. 820–891), patriarch of Constantinople, saint of the Orthodox church, was a scholar, public minister, diplomat, professor, organizer of missions, ecclesiastical writer, and hierarch. Photios was born into a noble family. His father, Sergius, was the brother of the patriarch Tarasios. Three of Photios's four brothers held high civil offices; because of his family's social position, he was able to obtain an advanced education.

In 850, when the university of Constantinople was reorganized (by Photios at the empress's request), Photios was one of the first professors called there to teach. He was sent to Baghdad in 851, together with Constantine the Philosopher, as diplomatic representative of the emperor to the caliph al-Mutawakkil. After intervention in 858 by the caesar Bardas, uncle of Michael III, the conservative patriarch Ignatius resigned. Photios as a layman was elected patriarch. Although he was eventually ordained, Nicholas I refused to recognize his election, and, under pressure...