One particularly successful exercise in patriarch-baiting

Nicholas's conception of papal authority extended, it need hardly be said, over the churges of the East. At this time the patriarch of Constantinople was a eunuch named Ignatius--a blinkered bigot loathed by his flock, which was determined to get rid of him. The leader of that flock was Photius, the most learned scholar of this day, capable of running rings around Ignatius, whose mind was too narrow to encompass any but the simplest theological doctrines. In one particularly successful exercise in patriarch-baiting, Photius even went so far as to propound a new and deeply heretical theory that he had just thought up, according to which man possessed two separate souls, one liable to error, the other infallible. His dazzling reputation as an intellectual ensured that he would be taken seriously by many--including, of course, Ignatius, who should have known better; and after his doctrine had its desired effect by making the patriarch look thoroughly silly he had cheerfully withdrawn it. It was perhaps the only completely satisfactory practical joke in the history of theology, and for that alone Photius deserves our gratitude.

Norwich, John Julius. Absolute Monarchs: A History of the Papacy. NY: Random House, 72-73. Print.