"Many of them held positions as chief architects, overseeing royal construction projects, and making outstanding contributions to architectural skill and craftsmanship," Bai says.

Yangshi Lei archives include architectural drawings, textual records, and three-dimensional models of construction projects, she explains.

In addition to the collection in the national library, others have been preserved mostly at the Palace Museum, the National Museum of China, and institutes of higher learning in China and abroad. In 2007, Yangshi Lei Archives were included in the UNESCO Memory of the World.

Bai says it's important to clarify the significance of the archives before starting to study them.

First, they provide a real and complete representation of the design and construction process of Qing Dynasty architecture, offering firsthand information on various aspects of traditional Chinese architecture from that period, Bai says.

"Undoubtedly, the best means of studying ancient Chinese architecture today is through the examination of the well-preserved ancient buildings themselves. However, buildings represent the final product, and we cannot understand the construction process simply by observing the architecture," she says.

Yangshi Lei drawings and files, on the other hand, document the process of building, the evolution of history, and even record communications and exchanges among personnel at all levels, and embody the architectural philosophy and ideas of ancient people, she explains.