The Chinese New Year, according to legend, originated from Zhuan Xu, one of the Three August Ones and Five Emperors, and has a history of more than 3,000 years. The term "Yuan Dan" first appeared in the "Jin Shu": "Zhuan Di took the first month of summer as the beginning, and it was indeed the first day of spring on the new year." During the Southern and Northern Dynasties, the Southern Dynasty scholar Xiao Zi Yun's poem "Jie Ya" also recorded: "New Year of the four seasons, the first day of the new year." In the Song Dynasty, Wu Zi Mu's "Meng Liang Lu" in the first volume "January" entry said: "On the first day of January, it is called Yuan Dan, commonly known as the new year. It is the beginning of the annual cycle." In the Han Dynasty, Cui Yuan's "San Zi Cha Ming" referred to it as "Yuan Zheng"; in the Jin Dynasty, Yu Chan's "Yang Du Fu" called it "Yuan Chen"; in the Northern Qi Dynasty, the "Yuan Hui Da Xiang Ge Huang Xia Ci" referred to it as "Yuan Chun"; in Tang De Zong Li Shi's poem "Yuan Ri Tui Chao Guan Jun Zhang Gui Ying", it was called "Yuan Shuo".
In the excavation of the Dawenkou cultural relics, an image was found showing the sun rising from the mountain peak, with clouds and mist in the middle. After verification, this is the oldest way of writing the character "Dan" in China. Later, in the bronze inscriptions of the Yin-Shang dynasty, the character "Dan" appeared in a simplified form. The character "Dan" is represented by a round sun. The "one" below the "sun" represents the horizon, meaning the sun rises slowly above the horizon.
The Chinese New Year has traditionally referred to the first day of the first month of the lunar calendar (Chinese lunar calendar). "Yuan" means "initial" or "beginning," and "Dan" refers to "day," so "Yuan Dan" means the "first day" of the year, which is the first day of the year. In various Chinese dialects, it has different names, such as "Big New Year's Day," "Big Tian New Year's Day," or "First Day of the Year," commonly called "First Day of the First Month."
The starting date of the first day of the first month was not unified before the reign of Emperor Wu of Han. Therefore, the months and days of the New Year varied across dynasties. The Xia Dynasty used the first month (January) of the Xia calendar as the first month, the Shang Dynasty used the twelfth month (December) of the Yin calendar as the first month, and the Zhou Dynasty used the eleventh month (November) of the Zhou calendar as the first month. After Emperor Qin Shi Huang unified China, he used the tenth month (October) of the Yangchun calendar as the first month, meaning that the first day of October was the New Year. From Emperor Wu of Han onwards, the first month (January) of the Mengxi calendar was set as the first month, and the first day of the first month (the first day of the lunar calendar) was called "Yuan Dan," which continued until the end of the Qing Dynasty. However, this was the lunar calendar, not the New Year as we know today.

In 1911, the Xinhai Revolution led by Sun Yat-sen overthrew the Qing Dynasty and established the Republic of China. Representatives of provinces held a meeting in Nanjing and decided to use the Gregorian calendar, calling the first day of the lunar calendar "Spring Festival" and the first day of the Gregorian calendar "Yuan Dan." However, it was not officially announced or named at the time. To "follow the Xia calendar for the sake of the farming season, and follow the Western calendar for the convenience of statistics," the first year of the Republic decided to use the Gregorian calendar (which was actually implemented in 1912), and stipulated that January 1st of the Gregorian calendar be called "New Year," but not "Yuan Dan."
The "Yuan Dan" we refer to today was determined on September 27, 1949, just before the founding of the People's Republic of China. At the first session of the Chinese People's Political Consultative Conference, while deciding to establish the People's Republic of China, it also decided to adopt the universally used Gregorian calendar, which is the solar calendar we now call.

Today, "Yuan Dan" refers to the first day of the year in the Gregorian calendar. To distinguish between the lunar and solar new years, and considering that the "Lichun" (Start of Spring) in the 24 solar terms falls around the lunar new year, the first day of the lunar first month was renamed "Spring Festival," and January 1st of the Gregorian calendar was set as the beginning of the new year, "Yuan Dan," and was listed as a public holiday, becoming a joyful festival for the people of China.