What does AD mean?

A.D., that is, Gregorian calendar chronology, is a kind of chronology that originated from western society. Julian calendar was originally called the Christian era, also known as the Gregorian calendar or the year of A.D., which was reformed by Italian doctor and philosopher aloysius Lilius. The Gregorian calendar originated from the annals. In A.D. 1582, the then Pope Gregory XIII approved the promulgation of this law.

In the second year after the outbreak of the Revolution of 1911 (19 12), the then government of the Republic of China adopted the Gregorian calendar as its national calendar. In terms of chronology, the chronological method of the AD and the chronological method of the Republic of China go hand in hand.

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.

Usage:

A. D. is the title and system of chronology. The chronology takes the birth of Jesus as the first year of AD, and before the first year of AD it is called BC. The so-called year 2020 is the year from the first year of AD.

It should be noted that although 0 is a natural number, it did not exist in 0 BC or 0 AD. The year after BC 1 year is AD 1 year, that is, the first year of AD.

Although the calendar year of BC is reversed, the figures behind it are smaller than the previous figures. For example, 202 BC (the calendar year established by the Western Han Dynasty) is later than 22 BC 1 year (the calendar year established by the Qin Dynasty), but the specific months of each year are still counted, with1in front and 12 behind, and the date is the same.

Extended data:

Universal calendar:

The calendar and calendar year of People's Republic of China (PRC) (China) adopts the Gregorian calendar of most countries in the world, but it still uses the traditional lunar calendar of China, which was decided by the first plenary session of the China People's Political Consultative Conference in September 1949.

At the meeting, everyone agreed that the calendar system commonly used in most countries in the modern world should be adopted, that is, the year of New China should be the year of the West. On September 27th, the second of the four resolutions adopted at the first plenary session of China People's Political Consultative Conference was: "The Gregorian calendar year is adopted in People's Republic of China (PRC)".

There are many methods of chronology in countries around the world, including Ganzhi Chronology, Taoism Chronology, Emperor Chronology, Astronomy Chronology, History Chronology and so on. In addition, there are Buddhist chronology, Islamic chronology, Jewish chronology, Japanese chronology, Greek chronology and so on.

As early as ancient times, there was a saying in some places in China that the ten-day trunk and the twelve-day branch were combined separately, and every 60 years was a cycle.

In modern times, the era of the Yellow Emperor was used. The so-called "Yellow Emperor Chronology" is a chronological method with the legendary year when the Yellow Emperor was born as the first year. It is said that the Yellow Emperor was born in 2698 BC. "The era of the Yellow Emperor" was put forward by Liu in the National Newspaper in the 29th year of Guangxu reign (1903). The age of the Yellow Emperor is calculated according to the Gregorian calendar.

References:

Baidu encyclopedia-A.D.