Who was Sanqing in ancient China?

Sanqing is the collective name of Taoism for the three highest gods it worships. These three supreme gods refer to: "There was a tiny sky in the early Qing Dynasty, a spiritual treasure in Yu Yu in the upper Qing Dynasty, and a great day in Taiqing." . Among them, the so-called Jade Qing realm, Qing Qing realm and Tai Qing realm are the differences in the fairyland where they live. Wei Qing sky, fish and rainy day and big red sky are the divisions of the celestial world, while the Buddha means that the respect for Tao is supreme, so it is named Buddha. It was only in the Jin Dynasty that the Covenant of the Buddha at the beginning of the Yuan Dynasty appeared among the Taoist gods. It is said that it is produced by green gasification of red mixed hole. Every time the doomsday ends and the world opens, they come out to teach secret passages and rob people. Lingbao Tianzun appeared among Taoist gods, but it appeared later than Yuanshi Tianzun in the Southern and Northern Dynasties. It is said that it is the product of the mixed spirit of Taiwuyuan and Huangxuan, also known as Taishang Daojun, and it was also transported away with the robbery. The moral heaven is Laozi, also known as Taishang Laojun. In order to form the hierarchical sequence of respecting gods in Sanqing, it is said that it was born from the mysterious gasification. In fact, Taoism respected Laozi as the leader from the time of its establishment, and further said that he was the ancestor of the God King in the Five Mountains. I am the Lord of flying immortals, I have become the supreme god, and I am often in two places, without the world. However, in the Sanqing, its status was the lowest, which obviously did not conform to the beliefs of all Taoists. So later, there was a saying that "one gasification and three cleanings". Why is there a saying of "one gasification and three cleanness"? Compared with Buddhism, Taoism rose late. During the prosperous period of Taoism, Buddhism was introduced into China, which had a great influence. Taoism should overwhelm Buddhism. At that time, when Taoism was born, Laozi was the earliest ancestor, and Laozi's Tao Te Ching was regarded as the main classic. Later, Taoism felt that it was not enough to have only the old gentleman, and it could not compare with the "three buddhas" and "three buddhas" of Buddhism, so it created the Yuanshi Buddha and Lingbao Buddha and formed the "Sanqing Buddha". This "one gasification and three cleanses" can be said to be a replica of the Buddhist "III Buddha". In other words, many gods in Taoism study Buddhism from top to bottom. These three gods have statues in the larger palaces of Taoism, which are called "Sanqing statues". At first, the Buddha was in the middle, Lingbao Buddha was on the left and Moral Buddha was on the right. At the beginning of the Yuan Dynasty, the Buddha's left hand was empty and his right hand was empty, symbolizing the "infinity" when the world was invisible and everything was chaotic. Lingbao Buddha holds a half-black and half-white circular "mirror of Yin and Yang" in both hands, symbolizing "Tai Chi" derived from the "infinite" realm; The moral Buddha holds a fan with a mirror of yin and yang, which symbolizes the "two instruments" of heaven and earth (or the "two instruments" of yin and yang) differentiated from "Tai Chi". Taken together, it is a Taoist cosmic schema, which embodies the Taoist world view.