What's the ancient September 1st?

In ancient China, there was no Gregorian calendar, but the lunar calendar was used. The first day of September in the lunar calendar is usually called September 1st.

The first day of September in the lunar calendar is not the same as September 1 in the current Gregorian calendar.

The lunar calendar is a traditional calendar in China, but it is not a lunar calendar, but a combined calendar of yin and yang. Taking the cycle of the moon phase as the length of the month and referring to the length of the tropical year, the average calendar year is adapted to the tropical year by setting 24 solar terms and leap months.

AD, Gregorian calendar era, originally called Christian calendar, also known as Gregorian calendar or AD, is a kind of chronology that originated from western society. This should start from the year when Jesus was born. Before the birth of Jesus, it was called "BC". However, in order to dilute its religious color and avoid the antipathy of non-Christians, modern scholars mostly change its names to AD (abbreviated as C.E.) and BC (abbreviated as B.C.E).

1On September 27th, 949, with the approval of the first plenary session of China People's Political Consultative Conference, the newly established People's Republic of China (PRC) adopted the Gregorian calendar and AD calendar commonly used in most countries in the world. However, the lunar calendar has not been abolished. Today, traditional festivals in China are still based on the lunar calendar.

Extended data:

China is one of the earliest countries that invented the calendar in the world, and its appearance has had a far-reaching impact on the country's economic and cultural development.

The Han calendar is one of the traditional calendars of Han nationality and China, also known as lunar calendar, lunar calendar, ancient calendar, yellow calendar, summer calendar and old calendar.

The Han calendar belongs to the lunar calendar. On the one hand, the moon revolves around the earth in the unit of "month", and the average month length is equal to "the first moon", which is the same as the lunar calendar principle, so it is also called "lunar calendar". On the other hand, the "leap month" is set to make the average length of each year as close as possible to the tropic year, and the 24 solar terms are set to reflect the characteristics of seasonal changes. Therefore, the Han calendar combines the characteristics of the Yin-Yang calendar, also known as the "Yin-Yang calendar".

Up to now, almost all China people in the world, as well as countries such as the Korean Peninsula and Viet Nam, still use the Han calendar to calculate traditional festivals such as Spring Festival, Mid-Autumn Festival and Dragon Boat Festival. ?

Baidu Encyclopedia-Common Knowledge of China Ancient Culture (Calendar-Calendar, Calendar and Day)