In the southwest suburbs of Beijing, the capital city of China, there are several mysterious caves on a high mountain. These caves are filled with stone slabs with Buddhist scriptures engraved on them. According to research, these stone slabs are about 1,400 years old. Who dug these caves? Why are these stone slabs in there?

The information contained in the above post is interesting though I can't surmise who dug the chambers.  Is it possible they were created by slave labour (though whose slaves I have no idea).