Who is the author of the mysterious pagoda monument?

Pei Xiu in Tang Dynasty

The full name of the Mysterious Pagoda is "A Record of Monks in Zuojie, Tang Dynasty, in which Three Religions Talk about Leading Dade to ankokuji's Seats, and the Mysterious Pagoda Monument is inscribed and prefaced", written by Tang Pei Xiu and sealed by Liu Gongquan. The Mysterious Pagoda Monument was established in December of the first year of Tang Huichang (AD 841), and the monument is in the forest of steles in Xi 'an, Shaanxi. Regular script has 28 lines and 54 words.