What are the colors of glazed tiles commonly used in ancient palaces?

The hierarchical system of ancient feudal society was strict, and there were strict differences not only in architectural styles but also in the colors of glazed tiles.

Only the palace can use yellow glazed tiles as the roof. Other buildings, even government offices and palaces, are not allowed to lay yellow glazed tiles on their roofs.

Green glazed tiles, second only to yellow, are often used in buildings such as princes and ministers and religious temples.

Blue glazed tiles, representing the color of the sky, are only used in places where the sky is worshipped.

Black glazed tiles are generally used for low-level officials and wealthy families, but also for special places. According to the five elements, the water in the north belongs to black. The roof of the Wen Yuan Pavilion of the Forbidden City Library is black glazed tile, which represents the fire-fighting function of water, and the supporting rooms of the temple are also covered with black tile, which represents the low level, showing the idea of taking honour person as the center.