The
Sixteen Prefectures , more specifically the
Sixteen Prefectures of Yan and Yun or the
Sixteen Prefectures of You and Ji , comprise a historical region in northern
China along the
Great Wall in present-day
Beijing and
Tianjin Municipalities and northern Hebei and Shanxi Province, that were ceded by the
Shatuo Turk Emperor
Shi Jingtang of the
Later Jin to the
Khitan Liao dynasty in 938. The subsequent
Later Zhou and
Song Dynasties sought to recover the ceded northern territories. Most of the Sixteen Prefectures including the two principal cities, Youzhou (also called Yanzhou, modern Beijing) and Yunzhou (modern
Datong) remained in Liao hands until the 1120s, when the
Jurchens of the
Jin dynasty conquered the region. In 1123, the Jurchens ceded most of the territories except Yunzhou to the Song, but retook them in 1125. The loss of the Sixteen Prefectures exposed the plains of central China to further incursions by the
Jurchens (the ancestor of
Manchus) and the
Mongols.