18]The earliest known physical evidence[19] of tea was discovered in 2016 in the mausoleum of Emperor Jing of Han in Xi'an, indicating that tea from the genus Camellia was drunk by Han dynasty emperors as early as the second century BC.[20] The Han dynasty work, "The Contract for a Youth", written by Wang Bao in 59 BC,[21] contains the first known reference to boiling tea. Among the tasks listed to be undertaken by the youth, the contract states that "he shall boil tea and fill the utensils" and "he shall buy tea at Wuyang".[2] The first record of tea cultivation is also dated to this period, during which tea was cultivated on Meng Mountain (蒙山) near Chengdu.[22] Another early credible record of tea drinking dates to the 3rd century AD, in a medical text by Hua Tuo, who stated, "to drink bitter t'u constantly makes one think better."[23] However, before the mid-8th century Tang dynasty, tea-drinking was primarily a southern Chinese practice.[24] Tea was disdained by the Northern dynas