Which period of the Han Dynasty is the first month of the year?

In the history of our country, the first month was formally established in the period of Emperor Wu of Han Dynasty.

Hanshu recorded the history of this system. In the seventh year of Emperor Wu of the Han Dynasty, a surname ordered Sima Qian to write to Sun Qing and Hu Sui, doctors of traditional Chinese medicine, saying, "It's useless to learn from bad experiences, but it's better to change them into new ones". After consulting Dr. Er Kuanhe, Emperor Wu of the Han Dynasty ordered Sima Qian and others to "discuss the opening of the Han calendar". Recruit national famous astronomers to participate.

There are more than 20 official and non-governmental experts, including assistant minister Zunda, Dianxing Shexing, Zhili, Changle Sima Ke, Jiuquan, alchemist and Baxian Luoxiahong. Not only did they work together in Qi Xin, but they also gave full play to their respective expertise and worked out more than ten calendars. That is, more than ten kinds of stepping schemes, after strict screening, decided to adopt Deng Pingli. Grand calendar ceremony, and change Yuanfeng seven years as the first year, so the new calendar is called "taichu calendar".

Extended data:

Hanshu recorded the history of this system. Emperor Wu of the Han Dynasty attached great importance to this calendar. Recruit national famous astronomers to participate. There are more than 20 official and non-governmental experts, including assistant minister Zunda, Dianxing Shexing, Zhili, Changle Sima Ke, Jiuquan, alchemist and Baxian Luoxiahong. They not only work together, but also give full play to their respective expertise. * * * has formulated more than ten calendars, that is, more than ten push-pull schemes. After strict screening, they decided to adopt the Deng Ping calendar.

Emperor Wu of the Han Dynasty was held in Tang Ming. Although Sima Qian was in mourning as an official and Emperor Wu of the Han Dynasty went on patrol, he was still asked to be an attache. Therefore, in the second year of Yuanfeng, Emperor Wu's retinue was blocked by the river to pay for it. Sima Qian was robbed, which shows that the monarch and the minister know each other at this time. Grand calendar ceremony, and change Yuanfeng seven years as the first year, so the new calendar is called "taichu calendar". After the promulgation of the calendar, the political system, regulations, etiquette and official system were adjusted, which was the initial restructuring of Emperor Wu of the Han Dynasty.

Baidu Encyclopedia-Tai Chu Calendar