Guan Yu was a historical general of the late Han dynasty (died 220 CE), a sworn brother of the warlord Liu Bei, whose fame as a warrior of matchless loyalty and integrity grew after his death until he was raised to the status of a god. Celebrated above all in the great historical novel Romance of the Three Kingdoms, the red-faced, long-bearded Guan Yu became the very embodiment of loyalty and righteousness (yi), and successive dynasties heaped honorific titles upon him, promoting him over the centuries from duke to king and at last to emperor and god, Guandi, the Emperor Guan.
The stages of Guan Yu's posthumous promotion are documented with real precision in imperial records: the Song dynasty first ennobled him as a duke in 1102, raised him to the rank of king later in the same dynasty, and the Ming dynasty's Wanli Emperor formally proclaimed him a full god and emperor, Guandi, in 1614, a title the Qing dynasty subsequently confirmed and further embellished with an ever-lengthening string of honorific epithets. Few individuals anywhere in world religious history have so complete a paper trail charting their transformation, step by dated imperial decree, from an executed general into one of the most widely worshipped deities of an entire civilisation.