This incident seems to give people the impression that the yellow robe is the emperor's exclusive clothing. In fact, before the Song Dynasty, the imperial court had made many restrictions on the clothes of its subjects. In particular, it clearly stipulates what kind of clothes a king should wear and the decorations on his clothes. It is said that the Book of Rites and the Moon Order specifically recorded the laws and regulations at this time, and the emperor "kept Tsing Yi".
However, the Spring and Autumn Period and the Warring States Period was an era of collapse of rites and music. Zhou could not restrain the behavior of the princes, and the robes of monarchs in various countries were not uniform. Monarchs usually wear clothes in their favorite colors. For example, Qi Huangong likes to wear purple clothes. As a result, people in this country followed suit, which shows that purple clothes were not the patent of the king at that time.
But purple clothes are five times more expensive than ordinary clothes, and most people can't afford to wear such expensive clothes. At Guan Zhong's suggestion, Qi Huangong stopped wearing purple clothes, and people stopped wearing purple clothes after that. But since then, purple clothes have become a symbol of wealth and status.
During the Warring States period, the theory of "five elements" prevailed. After Qin Shihuang unified the six countries, the Qin Dynasty was established. Because the Qin dynasty was a water virtue, it advocated black things, and then the clothes and flags were all black. They use black clothes as a symbol of dignity and status. Then the Jin Dynasty implemented the Kinder system, and they thought red clothes were the noblest. Therefore, the emperors of the Jin Dynasty liked to wear red robes.
Later, the concept of five virtues declined, and then the emperor chose how to dress not only according to the five virtues. In the Sui Dynasty, both emperors liked to wear yellow robes, but no one was forbidden to wear yellow robes at this time. It was only in the period of Li Yuan in Tang Gaozu that people in the world were really forbidden to wear yellow clothes, and at that time, the colors and forms of other officials' clothes were also stipulated: officials with three or more products wore purple clothes, officials with four or five products wore red clothes, officials with six or seven products wore green clothes, and officials with eight or nine products wore blue clothes.
After that, the yellow robe became the emperor's clothes, and it was forbidden for others to wear yellow clothes, otherwise it would be disrespectful to the emperor. This rule lasted from the Tang Dynasty to the demise of the Qing Dynasty, and all the dynasties in the middle followed this rule. For example, in the Qing dynasty, except for the yellow jacket given by the emperor himself and the imperial guards guarding the palace, people all over the country were forbidden to wear yellow clothes.