How did the calendar come from?

Calendar is a set of calendars invented by the ancient Greek astronomer Sotchini, which was promulgated by the ancient Roman emperor Caesar and named julian calendar. This calendar originally stipulated that a year consists of 12 months, with 3 1 day in a single month, 30 days in a bimonthly month, 29 days in a normal year and 30 days in a leap year, and every four years.

The first complete calendar in the history of China-taichu calendar.

In the first year of Emperor Wu of the Han Dynasty (BC 104), the imperial court recruited more than 20 astronomers from all over the country to make calendars in Beijing. These include, Luo, Gong and Hu Sui. After their discussion, the early calendar was made. This calendar is the first complete ancient calendar handed down so far.

According to the taichu calendar law, the length of a month (the first lunar month) is 29.8 1 43 days (29.530864 days), including 12 months in a normal year,1month in a leap year and 7 leap months in 19 years. According to this calculation method, one year is 12 and 19 two months. The length of a year and January are two basic data for making a calendar. According to the data compiled by taichu calendar method, although the error is still very large, the accuracy is already very high for calendars thousands of years ago. Taichu calendar was implemented from the first year of Emperor Wu of the Han Dynasty in 104 BC until it was replaced by the calendar of the later Han Dynasty in 84 AD, and it was implemented until 188.