Why did the ancients call dragon and tiger turtles "four spirits"?

The ancients said: "black dragon, White Tiger, Suzaku, Xuanwu, the Four Spirits of Heaven, Fang Ye."

Qinglong, Baihu, Suzaku and Xuanwu are the four great beasts in the eyes of the ancients, and they are also called "Four Spirits". "Four Spirits" originated from ancient astronomical observation and the worship of stars by ancestors.

The ancients roughly divided the sky into four regions: the stars in the east combined into the image of a dragon, called "green (pale) dragon"; The western stars combine to form the image of a tiger, which is called "white tiger"; The stars in the south combine to form an image of a bird spreading its wings and flying, which is called "Suzaku (bird)"; The stars in the north combine to form an image of turtles and snakes, which is called "Xuanwu"

Extended data Qinglong:

Qinglong was originally the God of the East in China's ancient mythology, and one of the seven lodging and four elephants in Taoism. Twenty-eight lodging houses, and seven lodging houses in the East (Jiao, Kang, Bian, Fang, Xin, Wei and Fan) have the image of dragons, which are located in the East, belong to wood and are blue in color, collectively called Qinglong, also known as Black Dragon.

White tiger:

White tiger is also the god of war and war. The white tiger has many magical powers, such as avoiding evil, avoiding disasters, praying and punishing evil, promoting good, making a fortune, and tying the knot. And it is one of the four spirits, and of course it is also changed from the stars. be

Among these 28 stars, there are 7 in the west: osmium, building, stomach, ang, bi, Gou and Shen. Therefore, it is the representative of the west, and its whiteness is due to the west. The five elements belong to gold and the color is white. So it is called white tiger not because it is white, but because it comes from five elements.

Suzaku:

Suzaku does not belong to the phoenix, but one of the four spirits and four elephants. Like the other three schools, it comes from the stars and is the general name of the seven schools in the south: well, ghost, willow, star, Zhang, wing and Qi. Think of it as Suzaku.

Xuanwu:

Xuanwu is a spiritual thing composed of turtles and snakes. Xuanwu originally meant Xuanming, and the ancient sounds of Wu and Ming are interlinked. Xuan means black; Ghost means yin. At first, Xuan Ming described the turtle divination as follows: the turtle's back is black, and the turtle divination first invited the turtle to ask questions in the underworld, brought back the answers and showed them to the world in the form of divination.

References:

Baidu Encyclopedia-Four Spirits