The beginning of human activities within Yaan can be traced back to the Palaeolithic age and "Fulin Culture" is an important cultural site in the late Palaeolithic age of South China. In 316 BC, Qin conquered Bashu and set up Yandao County (the seat of county is located in current Yingjing), which is the earliest administrative area in Yaan. Western Military Prefecture was set up in the Western Han Dynasty. Yazhou Prefecture was set up in the 4th year of the Reign of Emperor Yang Jian in the Sui Dynasty (604). In the Tang Dynasty, enlistment and inclusion were offered to the frontier ethnic minorities and nearly one hundred Jimi autonomous prefectures governed by the chieftains of minority ethnic groups were set up in Yazhou and Lizhou. In the Northern Song Dynasty, the seat of Yazhou Prefecture was relocated to the piedmont of Cangping Mountain from Duoyingping. In the Yuan Dynasty, Yazhou Prefecture was under the jurisdiction of the Xuanwei commissioners of Tibetan Empire of Shaanxi Province. In the 7th year of the Reign of Emperor Yongzheng in the Qing Dynasty (1729), Yazhou was upgraded to Yazhou Prefecture, which covered the broadest jurisdiction area in the History of Yaan. In the 28th year of the Republic of China (1939), Xikang Province was set up and Yaan belonged to its second administrative inspection area. In 1950, Yaan was liberated and Yaan Prefecture was set up with Yaan as the capital city of Xikang Province. In 1955, Xikang Province was abolished and Yaan Prefecture was incorporated into Sichuan Province. In 1968, Yaan Revolutionary Committee was founded. In 1981, Yaan Prefectural Administration Office was set up. In December 2000, YaˇŻan was upgraded to Yaan Municipality (prefecture-level municipality). Yaan has witnessed many important events in its history, including Great Yu Harnesses the Flood, Money Making by Deng Tong, Shipbuilding in Yazhou, Rebellion of Liao People, Defeat of Shi Dakai at Dadu River, the Railway Project Crisis, Force Crossing of Dadu River and Climbing Jiajin Mountain of the Chinese Workers' and Peasants' Red Army, Battle of Baizhangguan and Yaan Uprising and nurtured many important figures, including Fan Min, Gao Yi, Lei Jianfu, Cao Guangshi, He Chongzheng, Wu Zhiying, Yue Yiqin, Cheng Zijian and Zhou Wen.