Kalmyk Khanate
About 200,000–250,000 Oirats migrated from western Mongolia to Volga River in 1607 and established the Kalmyk Khanate.The Torghuts were led by their Tayishi, Höö Örlög. Russia was concerned about their attack but the Kalmyks became a Russian ally and a treaty to protect the southern Russian border was signed between the Kalmyk Khanate and Russia. In 1724 the Kalmyks came under control of Russia. By the early 18th century, there were approximately 300,000–350,000 Kalmyks and 15,000,000 Russians. The Tsardom of Russia gradually chipped away at the autonomy of the Kalmyk Khanate. These policies, for instance, encouraged the establishment of Russian and German settlements on pastures the Kalmyks used to roam and feed their livestock. In addition, the Tsarist government imposed a council on the Kalmyk Khan, thereby diluting his authority, while continuing to expect the Kalmyk Khan to provide cavalry units to fight on behalf of Russia. The Russian Orthodox church, by contrast, pressured Buddhist Kalmyks to adopt Orthodoxy. In January 1771, approximately 200,000 (170,000) Kalmyks began the migration from their pastures on the left bank of the Volga River to Dzungaria (Western Mongolia), through the territories of their Bashkir and Kazakh enemies. The last Kalmyk khan Ubashi led the migration to restore Mongolian independence. Ubashi Khan sent his 30,000 cavalries to the Russo-Turkish War in 1768–1769 to gain weapon before the migration. The Empress Catherine the Great ordered the Russian army, Bashkirs and Kazakhs to exterminate all migrants and the Empress abolished the Kalmyk Khanate. The Kyrgyzs attacked them near Balkhash Lake. About 100,000–150,000 Kalmyks who settled on the west bank of the Volga River could not cross the river because the river did not freeze in the winter of 1771 and Catherine the Great executed influential nobles of them. After seven months of travel, only one-third (66,073) of the original group reached Dzungaria (Balkhash Lake, western border of the Qing Empire). The Qing Empire transmigrated the Kalmyks to five different areas to prevent their revolt and influential leaders of the Kalmyks died soon (killed by the Manchus). Russia states that Buryatia voluntarily merged with Russia in 1659 due to Mongolian oppression and the Kalmyks voluntarily accepted Russian rule in 1609 but only Georgia voluntarily accepted Russian rule.