Lev Gumilyov's book "The Search for a Fictional Kingdom" is one of the most famous and striking works of an outstanding historian and geographer. In this book, L.N. Gumilyov captivatingly, emotionally and in great detail tells about the life of the peoples of Central Asia of the 9th-13th centuries, and also explores the two least studied historical periods of our past: Kyiv Rus and the formation of a new Russian state in Muscovy. Could the kingdom of presbyter John become a reality and how would the course of world history change if it arose as a result of the defeat of Genghis Khan?