It was in the year 1224 that the first great Tartar invasion took place and that the hordes of Jenghiz Khan, the conqueror of China, Bokhara, Tashkent and Turkestan made their first appearance in the west. The Slavic armies were beaten near the Kalka river and Russia was at the mercy of the Mongolians. Just as suddenly as they had come they disappeared. Thirteen years later, in 1237, however, they returned. In less than five years they conquered every part of the vast Russian plains. Until the year 1380 when Dmitry Donskoi, Grand Duke of Moscow, beat them on the plains of Kulikovo, the Tartars were the masters of the Russian people.