Emperor Renzong of Song Dynasty, Zhao Zhen, was the son of Emperor Zhenzong. He ascended the throne in the first year of Qianxing (1022), with Empress Liu ruling from behind the curtain. In the second year of Mingdao (1033), after the death of the Empress, he began to rule personally. Emperor Renzong of Song reigned for 42 years, making him the longest-serving emperor during the Northern and Southern Song Dynasties. Regarding the background of Renzong, there is a story that has been passed down until today, which is the tale of "a racoon dog replacing the crown prince". The legendary experiences of the main characters in this story are almost known by everyone, including children and elderly women.