Whether it is the theory of five ancient capitals put forward by Liang Qichao and others (Chang 'an, Luoyang, Bianjing, Yanjing and Jinling) or the theory of six ancient capitals represented by Zhang Qiyun (Chang 'an, Luoyang, Kaifeng, Nanjing, Hangzhou and Peiping), or it has been put forward since the 1980s? Seven ancient capitals? 、? Eight ancient capitals? On the other hand, Xi 'an (Chang 'an) is the largest ancient capital, which fully highlights the central position of Xi 'an in ancient China.
Besides China's theory of great ancient capital, Xi 'an can even occupy a place in the world famous ancient capital. Among them, it is widely circulated that Xi 'an is called the four ancient capitals of the world together with Athens, Cairo and Rome.
Then, why is Xi 'an the only one favored by so many emperors in the past? Why hasn't a unified dynasty chosen to build its capital here since the Tang Dynasty?
In fact, this is closely related to the geographical and natural conditions of Xi. First of all, from a political point of view, Xi is located in the upper reaches of the Yellow River. The topography of China is generally higher in the west and lower in the east, which makes Xi 'an overlook Hedong. Going upstream to engage in Liuhe? Geographical advantage.
Sean, one of three outstanding heroes of early han dynasty, once praised this place? Thousands of miles away in Jincheng, a land of abundance? , but? Resist three sides, and control the princes at the same time. The princes are stable, the rivers and rivers hold the world, and the west gives the capital; The princes have changed, and they have gone down the river, enough to lose? . In ancient geomantic omen, Long Mai's occupation was usually emphasized, and Guanzhong, where Xi 'an was located, was called the dragon head, which was the ridge of the world.
Secondly, from a military point of view, Xi 'an is located in Guanzhong Basin, surrounded by mountains, which has existed since ancient times? 4. Blocked land? As the saying goes, advance can attack, retreat can defend. The whole Xi 'an is surrounded by mountains: there is a steep Huashan Mountain in the east, and its vein extends eastward to Lushan Mountain, spanning between the Yellow River and Luoshui; In the south, there are Taibai Mountain, Cuihuashan Mountain and Mount Li, which stand tall in the south of Guanzhong Plain with other people and valleys. In the north, Yaoshan, Huanglong Mountain and Cuoshan form a continuous Beishan mountain system. There are Qishan, Duyang Mountain and Chencang Mountain in the west, and the Gufeng uplift blocks the west of Guanzhong. There is a narrow pass above the mountain, with Hanguguan (now Lingbao County, Henan Province) and Chongguan (now Tongguan County, Shaanxi Province) in the east, Wuguan (now Danfeng County, Shaanxi Province) in the southeast, Dasanguan (now Baoji City, Shaanxi Province) in the west and Xiaoguan (now Guyuan County, Gansu Province) in the northwest. * * * together constitute a portal that is easy to defend but difficult to attack.
Then, from the economic point of view, Xi 'an is located in Guanzhong Plain, with fertile land, dense rivers and fertile fields, which is easy to cultivate. Therefore, it was developed earlier, and it was able to feed a large number of people from the pre-Qin period, so it was obtained. Land of abundance? Good name. Moreover, because the rivers in Xi 'an are criss-crossing and irrigation is convenient, it has existed since ancient times. Eight waters around Chang 'an? Statement. These eight rivers include: diameter, Wei, Yan, production, orange, ocean, high and waterlogging. Because of this, the Guanzhong area where Xi 'an is located has loose soil and fertile soil, which has become the cornerstone to support Xi 'an to become a land of abundance.
However, it may be that prosperity will inevitably decline, and the ancient capital Xi 'an has gradually declined. After the Tang Dynasty, it was no longer the capital of the unified dynasty. The reason is, first of all, the deterioration of its surrounding natural conditions. However, as the long-term capital of the Chinese Empire, the dense population far exceeds the carrying capacity of the land. Endless land development has caused great damage to the surrounding natural environment, and the beautiful environment in the past no longer exists, and the natural situation is deteriorating day by day.
According to statistics, the cumulative population from Kanto in the Western Han Dynasty alone exceeded 300,000. By the middle of the Western Han Dynasty, the descendants of these Kanto immigrants were about 1.2 1.6 million, which made the population of Guanzhong area where Xi 'an was located far exceed the limit that local grain production could bear. By the Tang Dynasty, the population of Guanzhong was even larger, and the population of Chang 'an City had reached 1 10,000, making it the most populous city in the world at that time. The huge population and the construction of huge palaces have greatly aggravated the damage to the local natural environment, which has led to soil erosion, river siltation, stagnant water transportation and the emergence of Beijing food crisis.
In addition, since the mid-Tang Dynasty, the global temperature turned cold, and Xi 'an lost its warm and humid climate, which greatly affected the development of local agricultural economy. Really? Eight waters around Chang 'an? After the Tang Dynasty, the prestigious Xi 'an water system was also destroyed due to the deterioration of water environment. The water quantity was greatly reduced and the grain transportation was interrupted, which further aggravated the grain shortage. Even in Tang Gaozong's time, because of the lack of food in Chang 'an, the whole court had to move to Luoyang for office.
Secondly, frequent regime changes have turned the once prosperous Chang 'an City into ruins. After the Anshi Rebellion broke out, the rebels attacked Tongguan, and Chang 'an, Tang Dou, fell for one year and three months, and the whole Guanzhong fell into disaster. After the Anshi Rebellion, the separatist forces in the buffer regions became more and more powerful, foreign invasion followed, and wars continued. It just happened? Changes in Shi Jing? Don? King Qin? Huang Chao Uprising Army was besieged by soldiers, the battle of Shayuan in Tongzhou, the Qi army conquered Chang 'an, besieged Fengxiang, and Zhu Wen plundered Chang 'an, which completely turned Chang 'an into ruins. Since then, the Song and Ming Dynasties have intentionally moved the capital here, but due to various factors, they can only give up.
In addition, since the Sui and Tang Dynasties, the economic center of gravity has gradually moved south. While the south of the Yangtze River is booming, the northern economy is depressed due to years of war. Xi 'an is no exception, and the national economic center of gravity and political center of gravity no longer coincide. It is precisely because of the shift of economic center of gravity to the south that it is not only difficult, but also costly to transport grain from the south to Guanzhong, which is more and more costly.
In the middle and late Tang Dynasty, solving the transportation problem of grain and materials became a crucial issue in the Tang Dynasty, and Chang 'an faced survival crisis for many times because of the interruption of grain transportation. In ancient times, when water transportation was obviously superior to land transportation, the inconvenience of water transportation undoubtedly caused a fatal blow to Xi 'an, and the capital city of Tokyo (Kaifeng) rose accordingly. In addition, after the demise of the Tang Dynasty, the Silk Road on land was cut off, the Maritime Silk Road rose, and the geopolitical plate in Northeast China rose, so the decline of Xi 'an, once the trade center of the Silk Road on land, was inevitable.