St Photios the Great

The most learned man of his age, Photios was a layman, professor, and imperial secretary when he was raised — within a week — through all the clerical orders to the patriarchal throne of Constantinople in 858. His Bibliotheca, reviews of hundreds of ancient books many of which are now lost, preserves whole stretches of classical and Christian literature. As patriarch he launched the mission of Cyril and Methodius to the Slavs and oversaw the conversion of Bulgaria, decisively shaping the future of Slavic Christianity. His clashes with Rome — over jurisdiction, over Bulgaria, and over the addition of the Filioque to the Creed, which he critiqued in his Mystagogy of the Holy Spirit — twice cost him his throne and left wounds between East and West that history has not forgotten. Deposed and restored amid palace politics he did not control, he died in exile in a monastery, honoured by the Church as a confessor of the faith and pillar of Orthodox theology.