Jin–Song Wars
The Jin–Song Wars were a series of conflicts between the Jurchen-led Jin dynasty (1115–1234) and the Han-led Song dynasty (960–1279). In 1115, Jurchen tribes rebelled against their overlords, the Khitan-led Liao dynasty (916–1125), and declared the formation of the Jin. Allying with the Song against their common enemy the Liao dynasty, the Jin promised to cede to the Song the Sixteen Prefectures that had fallen under Liao control since 938. The Song agreed but the Jin's quick defeat of the Liao combined with Song military failures made the Jin reluctant to cede territory. After a series of negotiations that embittered both sides, the Jurchens attacked the Song in 1125, dispatching one army to Taiyuan and the other to Bianjing (modern Kaifeng), the Song capital.