The construction of the tomb was described by historian Sima Qian (145–90 BCE) in his most noted work Shiji, written a century after the mausoleum's completion. Work on the mausoleum began in 246 BCE soon after Emperor Qin (then aged 13) ascended the throne, and the project eventually involved 700,000 workers.[3] Geographer Li Daoyuan, writing six centuries after the First Emperor's death, recorded in Shui Jing Zhu that Mount Li was a favoured location due to its auspicious geology, "famed for its jade mines, its northern side was rich in gold, and its southern side rich in beautiful jade; the First Emperor, covetous of its fine reputation, therefore chose to be buried there".[4][5] Sima Qian wrote that the First Emperor was buried with palaces,
