Phuong Hoang Trung Do is a citadel built by King Quang Trung (or Nguyen Hue) near the Lam river and Dung Quyet mountain; now in Vinh city, Nghe An province, Vietnam. The citadel was built in 1788. Here Quang Trung king gathered ten thousand troops before going to the North to reclaim Thang Long citadel at the time being invaded by the Thanh army. This citadel is intended to be built to replace the capital of Phu Xuan, named after the meaning of the Phoenix bird, a legendary bird. Trung Do also means that the capital is located in the middle of the territory controlled by Quang Trung, about 300 km from Phu Xuan, about 300 km from East Kinh Ke Market. Phuong Hoang Trung Do has two citadel walls called Inner Citadel and Outer-Wall Citadel, with circumference of 2820 m and an area of ​​22 ha. On April 28, 1998, the Ministry of Culture, Sports and Information of Vietnam issued Decision No. 313 / QD-VH to recognize Phuong Hoang Trung Do relics.