But in the thirteenth century, while this strange and finally ineffectual struggle to unify Christendom under the rule of the Pope was going on in Europe, far more momentous events were afoot upon the larger stage of Asia. A Turkish people from the country to the north of China rose suddenly to prominence in the world’s affairs, and achieved such a series of conquests as has no parallel in history. These were the Mongols. At the opening of the thirteenth century they were a horde of nomadic horsemen, living very much as their predecessors, the Huns, had done, subsisting chiefly upon meat and mare’s milk and living in tents of skin. They had shaken themselves free from Chinese dominion, and brought a number of other Turkish tribes into a military confederacy. Their central camp was at Karakorum in Mongolia. At this time China was in a state of division. The great dynasty of Tang had passed into decay by the tenth century, and after a phase of division into warring states, three main empires, that of Kin in the north with Pekin as its capital and that of Sung in the south with a capital at Nankin, and Hsia in the centre, remain. In 1214 Jengis Khan, the leader of the Mongol confederates, made war on the Kin Empire and captured Pekin (1214). He then turned westward and conquered Western Turkestan, Persia, Armenia, India down to Lahore, and South Russia as far as Kieff. He died master of a vast empire that reached from the Pacific to the Dnieper. His successor, Ogdai Khan, continued this astonishing career of conquest. His armies were organized to a very high level of efficiency; and they had with them a new Chinese invention, gunpowder, which they used in small field guns. He completed the conquest of the Kin Empire and then swept his hosts right across Asia to Russia (1235), an altogether amazing march. Kieff was destroyed in 1240, and nearly all Russia became tributary to the Mongols. Poland was ravaged, and a mixed army of Poles and Germans was annihilated at the battle of Liegnitz in Lower Silesia in 1241. The Emperor Frederick II does not seem to have made any great efforts to stay the advancing tide. Map: The Ottoman Empire before 1453 “It is only recently,” says Bury in his notes to Gibbon’s _Decline and Fall of the Roman Empire_, “that European history has begun to understand that the successes of the Mongol army which overran Poland and occupied Hungary in the spring of A.D. 1241 were won by consummate strategy and were not due to a mere overwhelming superiority of numbers. But this fact has not yet become a matter of common knowledge; the vulgar opinion which represents the Tartars as a wild horde carrying all before them solely by their multitude, and galloping through Eastern Europe without a strategic plan, rushing at all obstacles and overcoming them by mere weight, still prevails. . . .