Sixteen Prefectures
The Song dynasty was founded by Zhao Kuangyin (Emperor Taizu) (r. 960–976) in 960, before the Song completely reunified China proper by conquest—excluding only the Sixteen Prefectures. The Song fought a series of wars with the Liao dynasty (1125–1279), ruled by the Khitans, over the possession of the Sixteen Prefectures of northern China. The Liao regime was toppled in 1125 in a joint conquest by Song forces and the Jurchens led by Wuqimai (Emperor Taizong) (r. 1123–1134). However, the Jin quickly turned against the Song and invaded Song's northern territory. In what is known as the Jingkang Incident, Jin forces captured the Song capital, Bianjing (present-day Kaifeng), in 1127, along with Emperor Huizong ("r". 1100–1126), then a retired emperor, and his ruling son Emperor Qinzong (r. 1126–1127).