Gu Yanwu
In China, one of the first individuals to attempt a multi-dynastic history of the Great Wall was the 17th-century scholar Gu Yanwu. More recently, in the 1930s and 1940s, Wang Guoliang () and Shou Pengfei () produced exhaustive studies that culled extant literary records to date and mapped the courses of early border walls. However, these efforts were based solely on written records that contain obscure place names and elusive literary references.