A.D. 1: Also known as Gregorian calendar, its standard is the calendar method originated from western society. AD is often represented by a.d. (Latin abbreviation of Anno Domini, meaning "the year when the Lord was born"), while BC is represented by b.c. (abbreviation before Christ, meaning "before Christ"). This chronology method is closely related to western Christianity, because "Lord" refers to Jesus Christ. From the date of 1, it is now the year of 2023.
Tian Yun: This is an ancient method of numbering and dating in China, which comes from the chronology of trunk and branch in the lunar calendar. Therefore, Tian Yun is also called heavenly stems and earthly branches chronology. It is based on the combination of ten heavenly stems and twelve earthly branches, such as Wu Jianian and Wei Yingnian. This dating method is mainly used in the traditional culture of China, and it is still used in some occasions.
Generally speaking, AD can be traced back to Christianity in the West, while Tian Yun can be traced back to the traditional calendar in China. They have different historical and cultural backgrounds.