When we watch TV dramas or some portraits, we will find a problem. Guan Yu's image is always red-faced and bearded, and then he wears a green suit, especially a green hat on his head. People don't know the meaning of the green hat very well, so we will have questions. Why does Guan Yu, who is loyal and brave, wear such a color hat?
Generally speaking, cuckoldry means that the wife has done something to betray her husband. There are three typical records. One originated in the Tang Dynasty, saying that a woman hid another man at home, and just when her husband came back, in order to avoid being found out, she detained half a watermelon skin on her husband's head and persuaded him to go out to work. This is a kind of origin. The other is that it originated in the Yuan Dynasty, and the Mongols disdained the prostitutes of the Han people and made some men who worked in brothels wear green hats, but these statements were all later than the Three Kingdoms period, so it was naturally impossible to have these meanings at that time in Guan Yu.
But when we read the Romance of the Three Kingdoms, the description didn't say what hat Guan Yu wore, only that he wore a green shirt, so maybe this hat was just invented later. Of course, why Guan Yu wore green clothes? Personally, I think it is to shape Guan Yu's image of loyalty, justice and bravery, because green belongs to wood in the five elements, and wood is generally a manifestation of integrity. In ancient times, there was a saying called "loyal-hearted", which also meant loyalty to the liver and bravery. Therefore, letting Guan Yu wear a green robe should also reflect the meaning of "loyal-hearted".
Generally speaking, Guan Yu's cuckold husband is a result of film and television dramas, while green clothes are added to show his character.