Upon the ruins of his power arose that of Arabdan, the khan of the Songares. He subjugated the Northern Circuit, passed over into Turkestan, Tangout, and Khoten, and gradually reduced to his sway nearly all the elevated region of Central Asia west of Kansuh. He expelled the Tourgouths from their possessions in Cobdo, and compelled them to retreat to the banks of the Volga. Kanghí expelled the Songares from the districts about Koko-nor, but made no impression upon their authority in Songaria. After the death of Arabdan, about 1720, his throne was disputed, and the power weakened by dissensions among his sons, so that it was seized by two usurpers, Amursana and Tawats, who also fell out after their object was gained. Amursana repaired to Peking for assistance, and with the aid of a Chinese army expelled Tawats, and took possession of the throne of Arabdan. But he had no intention of becoming a vassal to Kienlung, and was no sooner reinstated than he resisted him; he defeated two Chinese armies sent against him, but succumbed on the third attack, and fled to Tobolsk, where he died in 1757. The territory of Arabdan then fell to Kienlung, and he pursued his successes with such cruelty that the Northern Circuit was nearly depopulated, and the Songares and Eleuths became almost extinct as distinct tribes. The banished tribe of Tourgouths was then invited by the Emperor to return from Russian sway to their ancient possessions, which they accepted in 1772; the history of the Chinese embassy to them, and their disastrous journey back to Cobdo over the Kirghís steppe and through the midst of their enemies, is one of the most remarkable instances of nomadic wanderings and unexampled suffering in modern times.[131] Chinese troops, emigrants, exiles, and nomadic tribes and families, were sent and encouraged to come into the vacant territory, so that erelong it began to resume its former importance. In the period which has since elapsed, the Manchus have been enabled to prevent any combination among the clans, and maintain their own authority by a mixed system of coercion and coaxing which they well know how to practise. The agricultural and mineral resources of the country have been developed, many of the nomads induced to attend to agriculture by making their chieftains emulous of each other’s prosperity, and by exciting a spirit of traffic among all.