There is an Yixian county in Baoding City, Hebei Province, which is famous for the Qing Xiling. Yong Zhengdi (Tailing Mausoleum), Jiaqing Emperor (Changling Mausoleum), Daoguang Emperor (Muling) and Guangxu Emperor (chongling) were all buried in the Qing Xiling Mausoleum. In fact, Yixian in history is a famous military town in the north, and it is also a battleground for military strategists. ? The terrain of Hebei Province is very complicated, with Taihang Mountain in the west and Yanshan Mountain in the north. East of Taihang Mountain and south of Yanshan Mountain is the endless North China Plain. Beijing is located at the junction of Taihang Mountain, Yanshan Mountain and North China Plain. Even before King Jin Hailing moved to Zhongdu (Beijing), Beijing was one of the important towns in the north, which was called Youzhou in ancient times. Youzhou is the Mongolian Plateau in the north, the Loess Plateau in the west, the Northeast Plain in the east and the North China Plain in the south, which was the land of the four wars in ancient times. Yixian is located in the east of Taihang Mountain, and not far from the north is the famous Xishan in Beijing. If there are troops occupying Youzhou, the soldiers in Hebei must first win Yixian if they want to get Youzhou, otherwise it is a dream. From the point of view of Youzhou, if you want to keep Youzhou, you must first keep Yixian, otherwise the door will open. ? Zhou Wuwang sealed Zhao Gong in the state of Yan (Zhao Gong himself stayed in the Zhou Dynasty and his descendants ruled the state of Yan). No matter during the Spring and Autumn Period and the Warring States Period, Yan was not a strong country. During the Spring and Autumn Period, the neighbors to the south of Yan State were the powerful Jin State and Qi State (Jiang Qi). By the Warring States period, the neighbors in the south had become powerful Zhao Heqi (Tian Qi), which Yan could not afford to offend. It is a good choice for Yan to defend its small territory. The north bank of Yishui is Yixian County. Yixian County is bordered by Yishui in the north, Laishui in the west and Taihang Mountain in the back. As long as Yan can hold Yishui and yi county (Wuyang is in the southern suburbs of yi county), Yan will have no worries. ? Qin Shihuang unified the six countries, and Yan was in the final struggle. Taizi Dan sent Jing Ke to Xianyang to meet Qin Shihuang with a map of Du Kang in an attempt to assassinate him. Qin Shihuang was very happy when he heard that Yan State was going to present a map of Du Kang. Du Kang is now north of Yixian, Zhuozhou and Gu 'an, and Qin Shihuang thought of it long ago. In addition, Taizi Dan gave Jing Ke a farewell dinner on the Xiao River not far from yi county. Yi county has Xishan in the north, Qigou in the east (where Qigou and Guanguan fought in the Song Dynasty) and Feihuling in the west. As long as we control Yixian, we can get Qigou Pass in the east and Yanmen in the north. Yixian is the east gate of Yanmenguan. The ancients gave lectures on the topography of the county: If Yixian is captured, the Wild Goose Gate cannot be defended. ? At the end of the Tang Dynasty, the importance of Yizhou was highlighted again because of the warlord regime. The warlords in the south did not mention that there are six major forces in the north, especially Hebei. In the north is the newly rising Qidan, and Yeluboji is eyeing Hebei. Zhu Wen, the strongest king of Liang in the Central Plains, is in the south, and Zhu Wen also intends to annex Hebei. In the west, Li Keyong (son of Li), King of Jin, was Zhu Wen's greatest enemy. Liu Shouguang, the prince of Yan, controls northeast Hebei, southeast Hebei, Beijing and Tianjin, and western Liaoning. Between the top four, there are two strong forces. In the south, there is Wang Rong, the king of Zhao, who controls Zhou Zhen (Zhengding, Hebei), Zhao County and Jizhou. There is an Yiwu army in the north, and its brother Wang Zhicun controls Dingzhou in the south and Yizhou in the north. Not far from Yizhou to the east is Zhuozhou controlled by Yan State, and not far from the west is Yuzhou controlled by Jin State. Zhao can only protect himself, Liu Shouguang, the prince of Yan, is cruel and incompetent, and Li, the king of Jin, has long wanted to annex Yan. Yizhou is one of the only places where Jin Jun attacked Yan. In the second year of Liang Ganhua (AD 9 12), Li decided to attack Liu Shouguang after Jin Jun attacked the north. ? In the spring of this year, Zhou Dewei, the general of the State of Jin, went through the customs from Daizhou (Daixian County, Shanxi Province) and attacked Qigou Pass of Yan State together with Zhao Bing and Yiwu Bing. After taking it, it directly passes through Xiao and enters Zhuozhou, the gateway of Youzhou. Zhuozhou surrendered without a fight, which scared the daylights out of Liu Shouguang, and he quickly asked Zhu Wen for help. Zhu Wen invasion again, it is impossible to destroy 8 jin j, and 8 jin j occupied zhuozhou, the door of the deep and remote states can't be closed. From the perspective of gold, the situation of taking swallows is very favorable. In the third year of Liang Ganhua (AD 9 13), Liu Shouguang was captured by the Jin army, which occupied a beautiful place. Imagine that if Yizhou was not in the hands of Yiwu soldiers, it would be difficult for Jinbing to kill Zhuozhou, and then it would not threaten Youzhou. When the state of Jin annexed Youzhou, the biggest threat was not the Liang Dynasty in the Central Plains, but the Qidan in the north. According to the risks of Taihang Mountain and Yanshan Mountain, Youzhou is a natural barrier for Qidan to go south to the Central Plains. Lu Ye Po can't sit still. He wants to rob Youzhou soldiers and Qidan soldiers from Li. Li knew that the Qidan army was mainly cavalry, and he was worried. General Li Siyuan said, I want to send troops to meet Baoji. With Lee's approval, Li Siyuan soldiers gathered on the Laishui bank. To the west of Laishui is Yizhou. In fact, Li Siyuan repeated the route of 8 Jin J destroying Yan before, and still used Yizhou as a springboard to go in and out of Youyan. Subsequently, the nomads from multiple routes came to Yizhou * * *, totaling 70,000 people. Nomads from Yizhou went north, crossed Dafangling, and rescued Youzhou, which was besieged by Qidan for more than 200 days. After World War I, the Khitan was defeated and the siege of Youzhou was solved. Yizhou played an important role in clearing the gap. ? Shi Jingtang, Emperor Wu of Jin Dynasty, ceded sixteen states of Youyun to Qidan, but not Yizhou. There is Yizhou in the Central Plains, which is very close to Youzhou controlled by Qidan, so it is very convenient to sneak attack. Qidan has no profit, and Zhuozhou has no danger to defend. When Yelvdeguang, Emperor Taizong of Liao Dynasty, went south to destroy gold, he got Yizhou first and then the access to the Central Plains. After Yizhou was controlled by the Khitan, the Khitan cavalry could enter and leave the Central Plains at will, which was a great threat to the Central Plains. In the sixth year of Zhou Xiande (AD 959), SHEN WOO Xionglue's Zhou Shizong Chai Rong made a northern expedition to Qidan. After Zhou Bing won Yizhou, the Khitans in Youzhou became frightened. A large number of Khitans fled Youzhou overnight, and many local people fled to Xishan for refuge. ? Chai Rong was forced to retreat because of illness, but taking Yizhou still posed a threat to Youzhou controlled by Qidan. After Zhao Kuangyin's generation, he continued to control Yizhou and mastered the strategic initiative of Youzhou. It's just that Zhao Kuangyin was born conservative and didn't have the guts to attack Youzhou. Zhao Guangyi had the courage to carry out the Northern Expedition, but he was not wise enough. He was beaten twice by Qidan soldiers, and Yizhou fell. If you get the Qidan of Yizhou, you can rest assured to stay in Youzhou. And the loss of Yizhou, for the Northern Song Dynasty, it is impossible to get Youzhou. As for the capture of Youyan Empty City (including Yizhou) in the Northern Song Dynasty at the end of Liao Dynasty, it was only the plan of Jin people to retreat for progress. For more historical and geographical articles, please pay attention to WeChat official account: Map Emperor.