Why are the coffins in ancient cemeteries well preserved?

The ancients were very particular about the choice of the cemetery, so under normal circumstances, the interior of the tomb would be kept dry all the year round, and the coffin would be specially treated to prevent insects from eating, so the unearthed cultural relics would be naturally preserved. When the tomb is closed, fuel will be put into it and the air will be used up; Others can be preserved for a long time after being isolated and sealed by charcoal and sealed by soil.

Incomplete preservation generally has the following reasons:

1. Graves were stolen and cultural relics were destroyed. At the same time, the cultural relics inside the cemetery came into contact with humid air again and were eventually oxidized or corroded.

2. The cemetery collapsed.

Extended data:

Historical evolution of ancient tombs;

From the Southern Song Dynasty to the end of Ming Dynasty and the beginning of Qing Dynasty, there were many military disasters, and several of the biggest natural disasters in the ancient history of China also appeared in this period. The national strength is weak, and the tombs of princes and nobles are not as luxurious as before.

Later, in the Qing Dynasty and Kanggan period, the national economy and productivity were greatly restored, and the architectural style of the mausoleum was also changed, paying more attention to the ground building and combining it with the ancestral temple garden. Drawing lessons from the anti-theft experience of past dynasties, the underground tombs in Qing Dynasty are extremely solid and the most difficult to start.

No matter which dynasty or generation, the forms of tombs in China for thousands of years all originated from the layout of the five elements of geomantic omen advocated by Fuxi's sixty-four hexagrams, and all insisted on occupying the world. In the final analysis, they are pursuing eight words: within nature, the harmony between man and nature.