In fact, using the word "official" to refer to the emperor is not unique to the Song Dynasty. Before the Song Dynasty, the word "official" had the meaning of emperor.
The earliest use of officials to address emperors was in the Southern and Northern Dynasties. At that time, Shi Hu, the later Zhao Dynasty, was dissatisfied with Emperor Schleswig and wanted to replace him. He asked his men, "It's hard to call an official. I want to do something rash. Do you understand what I mean? "
The butler here naturally refers to the post-Zhao emperor Schleswig.
However, it was not until the Song Dynasty that the word official was used to refer specifically to the emperor. Zhao Kuangyin established the Northern Song Dynasty from the mutiny in Chen Qiao. He is quite suspected of making a mistake about the country, even if he can't stop the leisurely mouth of the world. So he didn't dare to call himself the emperor, so he took out the words "official" and "home" in "On the History of the Three Kingdoms" written by Cao Wei and Jiang Ji.
On the one hand, the Three Emperors and Five Emperors themselves refer to emperors, hence the name "Emperor"; On the other hand, because the housekeeper has a public meaning, Zhao Kuangyin's move is intended to show the world that he represents not only the royal family, but public administration to show his selflessness and fearlessness.
Since the emperor spoke, the ministers and people in the Song Dynasty also called the emperor a butler, and gradually got used to it.
In fact, there were many titles for emperors in ancient China, and "Emperor" was just one of them. Some appellations are rarely heard today, but they do exist.
For example, in the Han Dynasty, emperors could be called "Tian Jia" and "Gong Ju".
Cai Yong said in "Dictatorship": "Heaven is called a hundred officials and small officials. The son of heaven is nothing more than taking the world as his home, so it is called Tianjia. "
Sima Qian's Biography of Xiao Wu in Historical Records reads: "I saw an old father holding a dog and saying,' I want to see a great man' and suddenly disappeared."
Also, in the Tang Dynasty, the emperor was even called "Zhai Jia".
Li Kuangyi in the Tang Dynasty said in Zi Ji Shu: "Gai takes the world as his home, and takes the world as his home. He dare not denounce it, so he calls it home, which is also your majesty's intention."
It can be seen that the names of emperors in past dynasties are very rich, so it may not be surprising to hear that people in the Song Dynasty called the emperor a butler.