Before Christ (meaning "before Christ/before the Lord"), abbreviated as B.C.), that is, before the first year of AD. Such as: BC 197, BC 8, etc. Xx BC, also known as "the first xx years".

Dating method

AD is a chronology. The so-called 20 14 years means 20 14 years from the first year of AD, and 20 14 years before BC 1 year.

It should be noted that there is neither 0 BC nor 0 AD, and the year after BC 1 year is AD 1 year (that is, AD 1 year). Although BC is counted backwards, the figures at the back are smaller than those at the front. For example, the establishment of the Western Han Dynasty in 202 BC was later than the establishment of the Qin Dynasty in 22 BC1year. But in the month of each year, it is still counting, with 1 in front and 12 behind, and the date is the same, with the first day in front and the fifteenth day behind.

A.D. (chronological system)

AD, the Gregorian era, originally known as the Christian calendar, also known as the 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, the then Pope Gregory XIII approved its promulgation.

It began in the year when Jesus was born. In julian calendar and Gregorian calendar, the date after the birth of Jesus is called the main year, and the date before the birth of Jesus is called the year before. 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 its national calendar. In chronology, the chronology of the AD is parallel to that of the Republic of China.

1949 On September 27th, approved by 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 the Gregorian calendar year, which are commonly used in most countries of the international community. However, the lunar calendar has not been abolished. Today, traditional festivals in China are based on the lunar calendar.