咸宜帝
In 1899, a French missioner, Léopold Cadière surveyed the customs and culture of the local inhabitants living along the Son River. In the letter to École française d'Extrême-Orient, he stated that: "What remains here proves to be valuable for history. To keep it is to help science". In the early 20th century, cave explorers and researchers from France and the UK discovered several ancient Champa and Vietnamese relics, such as altar, steles, hieroglyphic script, sculptures, stone statues, Buddha statues, and Chinese artifacts. King Hàm Nghi built a base for the Vietnamese resistance against the French colonialists in the late 19th century.