To the north, the boundary with Russian Siberia was fixed by the Treaty of Nerchinsk (1689) as running along the watershed of the Stanovoy Mountains. South of the Stanovoy Mountains, the basin of the Amur and its tributaries belonged to the Qing Empire. North of the Stanovoy Mountains, the Uda Valley and Siberia belonged to the Russian Empire. In 1858, a weakening Qing Empire was forced to cede Manchuria north of the Amur to Russia under the Treaty of Aigun; however, Qing subjects were allowed to continue to reside, under the Qing authority, in a small region on the now-Russian side of the river, known as the Sixty-Four Villages East of the River.