Please briefly introduce the history of Dunhuang in Han, Tang and Tang Dynasties.

"Dun, big also; Magnificent Dunhuang has a long history and splendid culture! As early as the end of primitive society, the Sanmiao people who migrated to Hexi after the defeat of the tribal war in the Central Plains flourished here. They focused on hunting and began to master primitive agricultural production techniques. Neolithic stone knives, axes, pottery and bronzes were unearthed in Dunhuang area. Dunhuang in Xia, Shang and Zhou Dynasties belonged to Guguazhou, and there were descendants of Sanmiao. At that time, Qiang people and Rong people settled nomadic here. Many rock paintings left by nomadic people found in Dunhuang area are still vivid. During the Warring States Period and the Qin Dynasty, the Dayue family, Wusun family and Sai family lived in Dunhuang. Later, Dayue became stronger and merged with the original Qiangrong. At the end of the Warring States period, Dayue people drove away Wusun people and Saizhong people and monopolized Dunhuang until the end of Qin Dynasty and the beginning of Han Dynasty.

In the early Western Han Dynasty, the Huns invaded Hexi and defeated the Vietnamese twice, forcing the Vietnamese to move westward to the two river basins (Syr Darya and Amu Darya). The whole Hexi Corridor is the territory of Huns. The powerful Xiongnu posed a serious threat to the Western Han Dynasty with the power of "more than 300,000 strings" and often harassed and plundered. After the clever Emperor Wu of the Han Dynasty succeeded to the throne, he adopted the strategy of both armed defense and active attack. In the second year of Jianyuan (BC 138), Zhang Qian was sent to the Western Regions for the first time to contact Yueshi and Wusun to attack the Xiongnu. In the second year of Yuanshou (12 1 years ago), the Han Dynasty decided to cut off the enemy's right arm and leave me alone and set out for Hexi Corridor. In the spring of the same year, Huo Qubing, the general of a title of generals in ancient times, was sent to command Wanqi from Longxi and marched into Hexi, winning a great victory. Not only the son of the evil king of Xiongnu and Ginkgo biloba were captured alive, but also the Xiongnu "Golden Sacrifice" was captured alive, which dealt a heavy blow to the Xiongnu forces in Hexi. Emperor Wu of the Han Dynasty placed this trophy in Ganquan Palace (Fengxiang, Shaanxi Province) for offering. This story is painted on the north wall of Cave 323 in Mogao Grottoes. On this day, Huo Qubing personally led the cavalry across the Juyan River and rushed to Qilian Mountain, killing more than 30,000 people, which caused a devastating blow to the Xiongnu forces in Hexi. At the same time, the Xiongnu ruling group clashed, and the evil king Xiongnu killed Xiutu and surrendered to the Han Dynasty with more than 40,000 people. In the second year of Ding Yuan in the Han Dynasty (1 15), Zhang Qian went to the Western Regions for the second time and returned to China smoothly from Wusun. Since then, the Silk Road to the Western Regions has been opened. Zhang Qian's "hollowing out" trip is a pioneering work in the history of Sino-Western exchanges, and it has made immortal historical contributions to promoting economic and cultural exchanges between China and foreign countries, the Central Plains and the Western Regions.

In order to completely cut off the contact between Xiongnu and Xiqiang, and maintain the security of the border crossing and the Silk Road, Emperor Wu of the Han Dynasty set up Jiuquan County and Wuwei County in Hexi in the second year of Yuanshou (12 1). And take measures such as fortification, reclamation and resettlement to continuously enrich and strengthen the construction of Hexi. In the sixth year of Ding Yuan in the Han Dynasty (11years ago), Jiuquan and Wuwei were respectively assigned to Dunhuang and Zhangye counties. From Lingju (now Yongdeng) to Yanze (now Lop Nur), the Great Wall and beacon tower were built, and Yangguan and Yumenguan were set up, which were called "four counties, according to two customs" in history, ensuring the smooth flow of the Silk Road. Since then, China's silk and advanced technology have spread to Central Asia, West Asia and Europe. Jade, agate, rare birds and animals, crops, etc. It was transported from Europe, the Mediterranean coast and the western region to the Central Plains. Ambassadors, soldiers, businessmen and monks from all over the world come and go in Dunhuang, the main road of the Silk Road. Dunhuang has become the "throat lock key" for Chinese and western traffic. At that time, Dunhuang had a vast territory and governed six counties. West to Longle Yangguan, east to Yolanda (now Yumen City West), north to Yiwu (now Hami City), south to Xiqiang (now Qaidam, Qinghai Province). After Dunhuang established a county, it laid a solid foundation for the Western Han Dynasty to govern the western regions. For example, Li Guangli, the general of the Second Division, defeated Dawanguo and won a bloody horse; Zhao Ponu defeated Gu, captured King Loulan, and used Dunhuang as a supply base for grain, grass and military forces.

In the early years of the Eastern Han Dynasty, the Huns grew stronger and conquered most of the western regions that were once under the jurisdiction of the Western Han Dynasty, and the Silk Road was forced to be interrupted. In 75 AD, the Eastern Han Dynasty sent troops to attack the northern Xiongnu in four ways. Dou Gu, a shepherd in Liangzhou, led his troops to defeat the Xiongnu in Hexi, recovered the lost land in Yiwu and reopened the gateway to the western regions. At the same time, Ban Chao, a famous soldier, sent two missions to the Western Regions, killed the Xiongnu envoys, contacted countries in the Western Regions and established friendly relations with the Eastern Han Dynasty, thus reopening the Silk Road which had been interrupted for 65 years.