Sixteen Prefectures

The Sixteen Prefectures of Yanyun (simplified Chinese: 燕云十六州; traditional Chinese: 燕雲十六州; pinyin: Yānyún Shíliù Zhōu) comprise a historical region in northern China along the Great Wall in present-day Beijing, Tianjin, and part of northern Hebei and Shanxi. It was a site of constant military and political conflict between various dynasties from the end of the Tang dynasty until the establishment of the Yuan dynasty.