Photios (810/820-891/893), patriarch of Constantinople (858-867, 877-886), was one of the dominant figures in the Byzantine religious, social, and political life of the ninth century. He was also one of the most prominent members of the Court of Constantinople and a protagonist in the controversy over the filioque clause (Dvornik 1948). His religious career is related to theological disputes, the restoration of icons, and political activities connected with missions to the Slavs. He laid the foundations of education, which made him one of the most famous scholars of the Byzantine Empire. He was interested in theological issues, grammar, poetry, rhetoric, philosophy, medicine, and law. His works are significant as evidence of the philosophical activities of the first half of the ninth century (Tatakis 1949; Lemerle 1971).
Most important for the history of philosophy is Photios’ Bibliotheca (sometimes called Myriobiblon), composed around 837/838, which is a collection of extracts of 280 volumes of classical authors, the originals of which are now to a great extent lost. In this work, he devoted several pages to preserve various ancient philosophical theories on free will and predestination (codices 214 and 251), skepticism (codex 212), and number symbolism (codex 187). He also compiled the Lexikon, a list ofnotable words, expressions, and references to facilitate the reading of sacred and secular authors, which was published later than the Bibliotheca. His most important work is the Amphilochia, a collection of some 300 questions and answers on difficult points in the Scripture, addressed to Amphilochius, the archbishop of Cyzicus. Amphilochia supplements the picture of Photios’ reading of classical philosophy, treating both theological problems and secular questions.
In Mystagogy of the Holy Spirit, Photios developed dialectical arguments against the Latin doctrine of the filioque. He remains faithful to the Orthodox dogma and always in agreement with traditional patristic and conciliar positions. He also wrote a treatise against the Paulicians, based on a similar work by Peter of Sicily, and his homilies contain abundant material for Byzantine political history and art. His many letters are addressed to popes, rulers, as well as military, civil, and church leaders.