What are the discoveries and studies about precession in ancient times?

As early as the 2nd century BC, Hippocrates, an ancient Greek astronomer, discovered the precession phenomenon that vernal equinox moved westward every 100 years by comparing the positions of ancient and modern stars.

With the gradual development of astronomy, scientists in ancient China gradually discovered precession.

Deng Ping, an official in the Western Han Dynasty, Liu Xin, a great scholar in the Eastern Han Dynasty, and Jia Kui, an astronomer, have all observed the phenomenon of winter moving to the future, but they have not clearly pointed out the existence of precession. It was not until the early years of the Eastern Jin Dynasty that astronomers began to affirm the existence of precession and advocated the introduction of precession into the calendar for the first time.