The career of conquest of Jengis Khan and his immediate successors astounded the world, and probably astounded no one more than these Mongol Khans themselves.
The Mongols were in the twelfth century a tribe subject to those Kin who had conquered Northeast China. They were a horde of nomadic horsemen living in tents, and subsisting mainly upon mare’s milk products and meat. Their occupations were pasturage and hunting, varied by war. They drifted northward as the snows melted for summer pasture, and southward to winter pasture after the custom of the steppes. Their military education began with a successful insurrection against the Kin. The empire of Kin had the resources of half China behind it, and in the struggle the Mongols learnt very much of the military science of the Chinese. By the end of the twelfth century they were already a fighting tribe of exceptional quality.
The opening years of the career of Jengis were spent in developing his military machine, in assimilating the Mongols and the associated tribes about them into one organized army. His first considerable extension of power was westward, when the Tartar Kirghis and the Uigurs (who were the Tartar people of the Tarim basin) were not so much conquered as induced to join his organization. He then attacked the Kin empire and took Pekin (1214). The Khitan people, who had been so recently subdued by the Kin, threw in their fortunes with his, and were of very great help to him. The settled Chinese population went on sowing and reaping and trading during this change of masters without lending its weight to either side.
We have already mentioned the very recent Kharismian empire of Turkestan, Persia, and North India. This empire extended eastward to Kashgar, and it must have seemed one of the most progressive and hopeful empires of the time. Jengis Khan, while still engaged in this war with the Kin empire, sent envoys to Kharismia. They were put to death, an almost incredible stupidity. The Kharismian government, to use the political jargon of to-day, had decided not to “recognize” Jengis Khan, and took this spirited course with him. Thereupon (1218) the great host of horsemen that Jengis Khan had consolidated and disciplined swept over the Pamirs and down into Turkestan. It was well armed, and probably it had some guns and gunpowder for siege work—for the Chinese were certainly using gunpowder at this time, and the Mongols learnt its use from them. Kashgar, Khokand, Bokhara fell and then Samarkand, the capital of the Kharismian empire. Thereafter nothing held the Mongols in the Kharismian territories. They swept westward to the Caspian, and southward as far as Lahore. To the north of the Caspian a Mongol army encountered a Russian force from Kieff. There was a series of battles, in which the Russian armies were finally defeated and the Grand Duke of Kieff taken prisoner. So it was the Mongols appeared on the northern shores of the Black Sea. A panic swept Constantinople, which set itself to reconstruct its fortifications. Meanwhile other armies were engaged in the conquest of the empire of the Hsia in China. This was annexed, and only the southern part of the Kin empire remained unsubdued. In 1227 Jengis Khan died in the midst of a career of triumph. His empire reached already from the Pacific to the Dnieper. And it was an empire still vigorously expanding.
Like all the empires founded by nomads, it was, to begin with, purely a military and administrative empire, a framework rather than a rule. It centred on the personality of the monarch, and its relations with the mass of the populations over which it ruled was simply one of taxation for the maintenance of the horde. But Jengis Khan had called to his aid a very able and experienced administrator of the Kin empire, who was learned in all the traditions and science of the Chinese. This statesman, Yeliu Chutsai, was able to carry on the affairs of the Mongols long after the death of Jengis Khan, and there can be little doubt that he is one of the great political heroes of history. He tempered the barbaric ferocity of his masters, and saved innumerable cities and works of art from destruction. He collected archives and inscriptions, and when he was accused of corruption, his sole wealth was found to consist of documents and a few musical instruments. To him perhaps quite as much as to Jengis is the efficiency of the Mongol military machine to be ascribed. Under Jengis, we may note further, we find the completest religious toleration established across the entire breadth of Asia.
At the death of Jengis the capital of the new empire was still in the great barbaric town of Karakorum in Mongolia. There an assembly of Mongol leaders elected Ogdai Khan, the son of Jengis, as his successor. The war against the vestiges of the Kin empire was prosecuted until Kin was altogether subdued (1234). The Chinese empire to the south under the Sung dynasty helped the Mongols in this task, so destroying their own bulwark against the universal conquerors. The Mongol hosts then swept right across Asia to Russia (1235), an 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.