Throughout Chinese history there have been several different theories regarding the authorship of the Mengzi. The famed Han Dynasty historian Sima Qian believed that Mencius himself wrote the book with the participation of his students Wan Zhang and Gongsun Chou. Zhu Xi, Zhao Qi, and Qing Dynasty Confucian scholar Jiao Xun believed that Mencius wrote the book himself without any participation from other scholars. Tang Dynasty writers Han Yu and Su Shi, as well as 12th century scholar Chao Gongwu, believed that Wan Zhang and Gongsun Chou wrote the book after Mencius' death from their own records and memories. Like all Chinese classics, the Mengzi has been annotated many times throughout history, but those of Zhao Qi, Zhu Xi, and Jiao Xun are considered the most authoritative.