Title: Dyo Byzantinoi hierarchai kai to schisma tēs Rōmaikēs ekklēsias
Subjects: Relations, Catholic Church, Orthodox Eastern Church, Schism, Eastern and Western Church
People: Nikolaos I Mystikos, Saint, Patriarch of Constantinople (852-925), Michael Cerularius, Patriarch of Constantinople (approximately 1000-1059), Photius I Saint, Patriarch of Constantinople (approximately 820-approximately 891)