Nikolai Afanasyevich Skabalanovich (1848–1918) is a professor of general and church history at the St. Petersburg Theological Academy, Doctor of Theology, one of the most talented Russian church historians. His seminal work, “The Byzantine State and Church...” is a veritable encyclopedia on Byzantium, a scientific work unsurpassed in many respects even to this day, including in its literary merits. The appendix contains the articles “Byzantine science and schools in the 11th century,” “On the morals of Byzantine society in the Middle Ages,” “The division of the Churches under Patriarch Michael Kerullarius” and others, which allow us to dwell with greater completeness and attention on specific issues such as the internal history of the Byzantine empire in general, and the history of the Byzantine Eastern Church in particular. For all those interested in the history of the Church and the historical destinies of Orthodoxy.