
During the fifth century, Pei Songzhi annotated the Sanguozhi by incorporating information from other sources to Chen Shou's original work and adding his personal comments. The authoritative historical source on Guan Yu's life is the Records of the Three Kingdoms ( Sanguozhi) written by Chen Shou in the third century. He is a deity worshipped in Chinese folk religion, popular Confucianism, Taoism, and Chinese Buddhism, and small shrines to him are almost ubiquitous in traditional Chinese shops and restaurants. In religious devotion he is reverentially called the "Emperor Guan" ( Guān Dì) or "Lord Guan" ( Guān Gōng). He is still worshipped by many Chinese people today.

Through generations of storytelling, culminating in the 14th-century historical novel Romance of the Three Kingdoms, his deeds and moral qualities have been given immense emphasis, making Guan Yu one of East Asia's most popular paradigms of loyalty and righteousness. Guan Yu's life was lionised and his achievements glorified to such an extent after his death that he was deified during the Sui dynasty. He was subsequently captured in an ambush by Sun Quan's forces and executed. By the time Guan Yu found out about the loss of Jing Province after his defeat at Fancheng, it was too late. In 219, while he was away fighting Cao Cao's forces at the Battle of Fancheng, Liu Bei's ally Sun Quan broke the Sun–Liu alliance and sent his general Lü Meng to conquer Liu Bei's territories in Jing Province. After Liu Bei gained control of Yi Province in 214, Guan Yu remained in Jing Province to govern and defend the area for about seven years. While he is remembered for his loyalty towards Liu Bei, he is also known for repaying Cao Cao's kindness by slaying Yan Liang, a general under Cao Cao's rival Yuan Shao, at the Battle of Boma.

Guan Yu played a significant role in the events leading up to the end of the Han dynasty and the establishment of Liu Bei's state of Shu Han during the Three Kingdoms period. Along with Zhang Fei, he shared a brotherly relationship with Liu Bei and accompanied him on most of his early exploits. Guan Yu ( ( listen) d. January or February 220 ), courtesy name Yunchang, was a Chinese military general serving under the warlord Liu Bei during the late Eastern Han dynasty of China. Guan's name in Traditional (top) and Simplified (bottom) Chinese characters
