The Stele of Virtuous Transformation of Nanzhao, erected within the ruins of Taihe City, is the most important stone inscription of the Nanzhao Kingdom. The stele is 3.02 meters tall and 2.27 meters wide, with an inscription of about 3,800 characters written by Zheng Hui, a Qingping official of Nanzhao. The inscription details the relationship between Nanzhao and the Tang Dynasty, the causes and course of the Tianbao War, as well as Nanzhao's political system and territorial extent, making it a "living history book" for studying Nanzhao history and Tang-Nanzhao relations. In 1961, it was announced by the State Council as one of the first batch of Major Historical and Cultural Sites Protected at the National Level.