Year number is a title given by the ancient emperor to record and calculate his reign year. The year numbers in ancient China appeared relatively late. Before the Western Han Dynasty, emperors did not have titles, but all titles were titles of kings. Is to use the king's numbers to record the years continuously until the new emperor ascended the throne. For example, from the first year of Zhou Pingwang to fifty-one years, from the first year of Luyin to eight years, from the first year of Qin Wang (Qin Shihuang) to the first year of Sanbu, and from the first year of Emperor Gaozu to twelve years. It was not until Emperor Wu of the Han Dynasty ascended the throne that this title appeared. When he acceded to the throne, he used the title of "Jianyuan". Therefore, Yan Shigu Liu Zuo, a scholar in the Tang Dynasty, noted: "Since ancient times, emperors have no year titles, which began here." Since Emperor Wu of the Han Dynasty, almost all emperors have titles. During this period, only when Tang Suzong was in office, he had no title for about half a year. After the year number appeared, there was a year number. In the ancient history of China, most new emperors ascended the throne, instead of continuing the calendar year of the previous emperor, they started from the second year and the first year. This practice of changing the name in the first year after the year is called changing yuan. The changes in the Yuan Dynasty occurred not only at the beginning of the new emperor's accession to the throne, but also during the reign of the emperor. That is to say, the emperor did not continue the existing chronological order in the middle of his reign, but re-chronicled from the first year, also known as the change of the yuan dynasty. In fact, this exchange of yuan first appeared in the time of Emperor Wen of Han Dynasty. Emperor Wen of the Han Dynasty reigned for 23 years and changed his name in 17. According to Records of Emperor Wendi in the History of Han Dynasty, in the sixteenth year of Emperor Wendi's reign, he got a jade cup in autumn and September with the inscription:' People should prolong their life'. Make the world bigger and exchange RMB next year. "That is, from 17, which is commonly known as the first year and the second year. Because there were two first years during his reign, when Ban Gu compiled Hanshu, he called the year after the end of the Yuan Dynasty "Hou Yuan". Later, during the reign of Jingdi 16, it was changed twice. Therefore, history books are also called "Central Plains" and "Hou Yuan". Since the reign of Emperor Wu of the Han Dynasty, whenever the Yuan Dynasty changed dynasties, the title of the year had to be changed. In the ancient history of China, Wu Zetian was the person who changed Yuan most frequently during his reign. She has been in office for 20 years and changed her title 17 times, so she has 17 titles. A little behind her was her husband, Li Zhi, who had been in office for 34 years and exchanged yuan 13 times. Ran was followed by Emperor Wu of the Han Dynasty, who reigned for 54 years and changed Yuan 1 1 times. As for the emperors who changed to Yuan Dynasty under 10, the number is even more. Many emperors have several titles because they changed the Yuan Dynasty many times during their reign. Until the Ming Dynasty, Zhu Yuanzhang, the emperor of the Ming Dynasty, had stipulated that the heir could only use one title, so except Ming Yingzong, who had two titles before and after the Cultural Revolution, all the others were the No.1 emperors. The Qing Dynasty also continued this practice and the emperors were unified. The reason why the ancient emperors changed to the Yuan Dynasty was mostly auspicious except for their new accession to the throne. In addition, there are disasters and strange natural phenomena, such as so-called auspiciousness, variation and so on. For example, Emperor Wu of the Han Dynasty captured a "white forest" in a hunting and ordered it to be changed to "Yuanshou". When Emperor Xuandi proclaimed himself emperor in the Western Han Dynasty, it was reported that a Huanglong was seen in Guanghan, Sichuan. In 229, Xuan Di ordered Huanglong to be renamed. During the Three Kingdoms period, Sun Quan of Soochow saw a Hong Niao, and in that year (238), he changed his name to "Hong Niao". These changes are all due to the sight of rare rare birds and animals, which are considered as auspicious signs. In 69 BC, a major earthquake occurred in Hanzhong, Shaanxi Province today, causing landslides and water gushing. Xuan Di, who was in office, ordered that the "Land Festival" be changed to "Land for its Festival". This is due to natural disasters. In many reforms, a considerable part is due to the turbulent situation or major events. Therefore, this title contains the desire for long-term stability. For example, during the Han and Yuan Dynasties, Hanting had a close relationship with Xiongnu, and Zhaojun went to the fortress and married Uhaanyehe. Since then, "there is no military revolution in the border areas, so it is better to change the yuan." (The Biography of Han Yuan Di) means border peace. Jung Uprising broke out in Xiao Zhuang of Northern Wei Dynasty. After the uprising was suppressed, Emperor Xiao Zhuang changed his name to Yong 'an. Most of these appellations are auspicious words. Such as Yongding, Yongchang, Yongping, Yongshi, Chang 'an and Changqing. Some of the reforms came after they gained the throne by extreme means. Therefore, most of these titles indicate that his accession to the throne is in line with God's will. It contains the intention of preaching the divine right of monarchy. With this title, you can hide your eyes and ears and your own misdeeds. For example, Wu Zetian's "Heaven Granted" and "Long Live the Book of Heaven". For example, Ming Yingzong regained the throne from his younger brother Jingtai Emperor through the restoration of the Nangong (the change of seizing the door). After he ascended the throne, he changed his name to "Tianshun". There are also some reforms for religious reasons. For example, during the Northern and Southern Dynasties, Buddhism prevailed. The Northern Wei Emperor Tuoba Tao believed in Taoism. Kou Qianzhi, a Taoist priest, catered to Mao's wishes and dreamed of being an old gentleman. Taizu ordered the painter to draw the statue of the old gentleman in Taishang according to Kou's dictation. And ordered it to be changed to "Taiping Town Army". Some of them have changed because of the completion of major projects. During the reign of Wu Zetian, a hall called Tian Tong Palace was built in Miyagi. When the main hall was completed, Wu Zetian changed it to "Long live the sky". Some people change their RMB to show their political inclinations and positions. Generally speaking, this kind of reform takes cadres and party branches as the year number. For example, in the early Tang Dynasty and the late Sui Dynasty, the peasant uprising army led by Dou Jiande established its own political power. In order to show no surrender to the Tang Dynasty, Ding Chou, the main branch of the year, was named the year number. Due to the change of the Yuan Dynasty, especially during the reign of the emperor, the year number and the year number were the same many times a year. Some of these auspicious names have appeared repeatedly in history. For example, Jianxing used 1 1 time, Tianshou used1time and Taiping used 9 times. As for the year number that has been used less than 8 times, the number of times is even more. For example, the familiar title of "Zhenguan" of Emperor Taizong of Tang Dynasty was also used during the reign of Emperor Chongzong of Xixia (1102 ~114). After Song Taizu Zhao Kuangyin ascended the throne, he ordered the Prime Minister to choose an unused title. Prime Minister Zhao Pu and others were dubbed "Gander". In the third year of Gande (965), Song Taizu unified the army to destroy Houshu. In the search of Houshu Palace, an old bronze mirror was found among the belongings carried by a maid-in-waiting. The back of the mirror is engraved with the words "Gander cast for four years". Song Taizu was frightened and asked the Prime Minister, "What has Andrew been casting for four years?" Zhao Pu and others can't answer. He also called Bachelor Tao Hub and Dou Yi to ask. "Iraq and Japan:' This must be a matter of Shu. Wang Yan, the puppet of Shu, used to have this title, which should have been cast by his age. "The above is a revelation, because he lamented:' The prime minister must use scholars. (Li Daochang's History as a Mirror, Volume 7) The phenomenon of the same year number appeared not only in different dynasties, but also in the same dynasty. For example, Huidi in the Western Jin Dynasty and Yuandu in the Eastern Jin Dynasty used the title of Jianwu: Tang Gaozong and Tang Suzong both used the title of Shangyuan; Yuan Shizu, the founding emperor of the Yuan Dynasty, and Yuan Shundi, the king of national subjugation, both used the title of "Zhiyuan", and so on. Different dynasties used the same title, but it is easy to confuse the same dynasty with the same title. Therefore, the appellation of ancient emperors in China should strictly distinguish between dynasties and emperors. There is no limit to the number of words used by ancient emperors. At least two or three words, at most six words. For example, after Yuan Wu, the first emperor of Xixia, proclaimed himself emperor, he used the title of "God-given courtesy and delay". The title of emperor in Ming and Qing dynasties is only two words, and he is the first emperor. So historians use the year number as the emperor name of the Ming and Qing emperors. For example, Emperor Hongwu, Emperor Yongle, Emperor Chongzhen, Emperor the emperor shunzhi, Emperor Kangxi and Emperor Qianlong. In the ancient history of China, the year number was often regarded as the symbol and symbol of the political power, which was directly related to the political power. Whether to use a certain year number has actually become a standard to measure and judge whether to recognize political power. Therefore, whenever a new regime is established, a new year number must be established. Both the peasant regime and some security regimes must have their own titles. Tao Qian, a Song Dynasty poet, was very dissatisfied with the autocratic power of Emperor Wu of the Eastern Jin Dynasty. The poet who resigned from his post and lived in seclusion was also praised for using Jia instead of Yixi for "How can it be a child in the village". Huang Tingjian, a poet in the Northern Song Dynasty, once called it "Jia Zi is not before Yi Xi". Before the Qing army entered the customs, Emperor Chongzhen hanged himself. However, after the Qing Dynasty made Beijing its capital, some people in the Ming Dynasty continued to use the title "Chongzhen" in their writings to show their nostalgia for the motherland. On the contrary, some people in the early Qing dynasty used the historical facts before the Ming dynasty entered the customs as the titles of the early Qing dynasty, such as destiny, Tiancong and Chongde. In this way, I expressed my yearning for the Qing Dynasty very early. In the late Qing Dynasty, Puyi reigned for three years, and the Revolution of 1911 broke out. In the past, revolutionaries no longer used the year of the Qing Dynasty. However, some Qing veterans still used the year number "Xuan Tong" to mark the year until the founding of the Republic of China. These examples all reflect people's understanding of the relationship between titles and political power. Since the year number came into being, the year number has been matched with the year of the main branch. Because the chronology of cadres and branches is a 60-year cycle, the same thousand branches often appear several times in a dynasty. If there is no other chronology method, it is difficult to determine which emperor is in office. But with the year number and year, the two complement each other, thus making the ancient year of China more accurate. Adding year numbers to the main branches is a great progress in the method of ancient chronology in China, and also a major feature of ancient chronology in China.