Zhongshan was a state in the Zhou Dynasty located in modern Ding County (定縣), Hebei Province. It first came under the protection of the State of Wei during the Warring States Period and later regained its independence for years. It was eventually absorbed into the state of Zhao. Area of today's Ding County had since become part of the ancient Zhongshan Commandry. The commandry capital Zhongshan city, was an economic center since the Eastern Han Dynasty until the Tang Dynasty. and the capital of Later Yan.