 After the overthrow of the Mongol Yuan dynasty by the Ming dynasty in 1368 , Manchuria remained under control of the Mongols of the Northern Yuan dynasty based in Mongolia . Naghachu , a former Yuan official and a Uriankhai general of the Northern Yuan dynasty , won hegemony over the Mongol tribes in Manchuria ( Liaoyang province of the former Yuan dynasty ) . He grew strong in the northeast , with forces large enough ( numbering hundreds of thousands ) to threaten invasion of the newly founded Ming dynasty in order to restore the Mongols to power in China . The Ming decided to defeat him instead of waiting for the Mongols to attack . In 1387 the Ming sent a military campaign to attack Naghachu , which concluded with the surrender of Naghachu and Ming conquest of Manchuria . 
