That is, the Gregorian calendar era, also known as Gregorian calendar or AD, is a method of chronology that originated in western society. This is a calendar made by Italian doctor and philosopher aloysius Lilius, who reformed julian calendar. 1582, Pope Gregory XIII approved its promulgation.

The year when Jesus was born is the beginning of a year. In julian calendar and Gregorian calendars, the date after the birth of Jesus is called the main year, and before the birth of Jesus is called the main year (English: Before Christ, abbreviated as B.C.). In order to dilute its religious color and avoid the antipathy of non-Christians, modern scholars mostly change their names to Common era (abbreviated as C.E.) and before Common Era (abbreviated as B.C.E).

The year after the outbreak of the Revolution of 1911 (19 12), the then government of the Republic of China adopted the Gregorian calendar as the national calendar, but it still adopted the chronological method of the Republic of China.

1949 On September 27th, the first plenary session of China People's Political Consultative Conference passed that the newly established People's Republic of China (PRC) adopted the Gregorian calendar and the Gregorian calendar commonly used in most countries in the international community as its own calendar and calendar year.

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