Photius, Patriarch of Constantinople, has been for a thousand years denounced by the Western Church as an arch-heretic and arch-schismatic of the Church and at the same time venerated in the East as a saint, scholar and a model churchman. Dr Dvornik reviews the whole history, reconsiders all the arguments, reconstitutes the facts, re-examines all the witnesses and comes to the conclusion that in the Photian case the Churchmen, Canonists and historians of the West were mistaken, that Photius was indeed a great churchman. In the second part of his book Dr Dvornik examines the reasons for this miscarriage of justice.