The book of the outstanding Church historian A.P. Lebedev (1845-1908) is dedicated to the image of the struggle between the Patriarchs of Constantinople and the popes, who sought to subjugate the entire Ecumenical Church. The main content of the book is the confrontation between two church parties: Ignatian and Fotian, named after their main leaders - the patriarchs of Constantinople Ignatius and Photius. It was this struggle, according to A.P. Lebedev, that had a great influence on the division of the Churches. The presentation of the material is in chronological order.