What is the knowledge behind naming an emperor, for example, what does Qianlong mean?

In fact, the names of emperors of the Qing Dynasty had a very strict set of regulations. Except for the last emperor Puyi, each of the twelve emperors of the Qing Dynasty had his own temple name, hanged name, title, reign name and so-called "Emperor of Daxing" and other titles.

The temple name is the title that the emperor placed in the ancestral temple (Fengxian Hall) after his death, such as: Taizu-Nurhachi; Shizu-Fulin; Shengzu-Xuanye; Gaozong-Hongli...

Hanhao - is the title given to the emperor after his death. This title will summarize the emperor's life deeds. The writing format required at that time was very strict. If you are not careful, it may happen at any time. Being punished or beheaded...

The name taboo is the emperor's own name, such as Nurhaci, Dorgon, Fulin, Xuanye, Yinzhen, Hongli... Before Fulin, he was The taboo on the emperor's name was not very taboo, but in the later years of Kangxi, taboos on the emperor's name began to be taken seriously. All taboo words related to the emperor's name must be "taboo", that is, the last point of "Xuan" in "Xuan Ye" cannot be written, and the middle vertical line of "Hua" (traditional Chinese characters) of "Ye" cannot be written.

And the "taboo" of this taboo is also very particular. It represents a royal privilege. If you accidentally forget this taboo, it can often lead to candidates failing the exam, officials being demoted or even dismissed. Discuss the crime that harms the clan members.

Year number - In the past, the calendar of ancient people was recorded according to the heavenly stems and earthly branches, but this had a drawback. It happens once every sixty years, that is, one reincarnation every sixty years. A person's lifespan is only two years at most, but it is a troublesome matter for a dynasty. Since the Yin and Shang Dynasties, there has been a method of recording by year number.

In fact, what we usually call "Kangxi" and "Jiaqing" should be the same era. The correct name should be "Kangxi Emperor" and "Jiaqing Emperor".

The "Emperor of Daxing" means that the emperor has died but has not yet been buried, and the new emperor has not yet ascended the throne. The deceased emperor at this time is called the "Emperor of Daxing".