Why is the Nandian Xuanfu Office known as the "Dai Ethnic Group's Forbidden City"?

The Nandian Xuanfu Office, located in Zhedao Town, Lianghe County, is a nationally designated key cultural relic protection site. In ancient times, this area served as a vital hub along the "Shu-Shendu Road." Nandian is an ancient name for the Lianghe region, derived from its position on a flat alluvial plain in the southern part of Tengyue Prefecture. During the Yuan Dynasty, a road was established here; by the early Ming Dynasty, it had become a prefecture, later reorganized into a state. In the ninth year of the Ming Zhengtong era (1444), the state was elevated to the Nandian Xuanfu Office, with the Tai族 Dao family hereditarily holding this prestigious position. The Dao clan, who ruled as local chieftains of Nandian, originally hailed from Shangyuan County in Nanjing’s Ying Tian Prefecture.