In the 1990s, scholars examined artifacts excavated two decades previously in Hebei, China, and discovered a large brass plate with an engraving for ZhaoYu Tu (translated as “map of the area of the mausoleum.”). The map was created during the 4th Century BC and it designated locations of several buildings in the five mausoleums of Emperor Wang Cuo—along with his empress, and even his concubines. It utilized symbols of numerals to indicate distances—quite an advanced method of mapmaking from such an early period—so it is also considered “the oldest numerals-bearing map in the world,” according to Du Naisong, a scholar at the Palace Museum in the Forbidden City of Beijing.
