For world history, the emergence of the military power Genghis Khan in the 13th century, which managed to subjugate many more developed civilizations of that time - China, almost the entire Muslim world, Russia and part of Eastern Europe - is an extraordinary phenomenon. It was of particular importance for the formation of Russian statehood. Based on numerous written sources, the author examines the features of the state mechanism of the Mongol empire, thanks to the effectiveness of which a relatively small people managed to conquer half the world. A large place in the book is given to the contribution of the Mongols to the development of military art of the Middle Ages, their tactics and strategies during the conquest campaigns of the first half of the 13th century.