Recommended resources on Russo-Byzantine world:
Johnson, Matthew Raphael. The Third Rome. Johnson’s thought matured since then, but this is the best (and most entertaining) beginning.
Wells, Colin. Sailing from Byzantium. The best intro to the Byzantine Empire. The sections on Holy Russia and Holy Serbia were simply beautiful.
Norwich, John J. Byzantium. The Classic scholarly English text.
Dugin, Aleksandr. The Last War of the World Island. The best intro to Eurasianism. It explains why the neo-liberal/neo-conservative West will spend trillions of dollars in a war Against Russia, and why Russia will fight to the death to prevent .