Before the Tang Dynasty, Chang'an was the perfect choice for the capital of the rulers of all dynasties. As for the ancient capital of several dynasties, there are still different opinions in the historians. Some say that it was the capital of the Ten Dynasties, the Fourteenth Dynasty, and the Seventeenth Dynasty. ... But one thing is clear: if Nanjing, the ancient capital of the Six Dynasties, fought with it, it would be far inferior.
The ancient rulers favored Chang'an so much because of its unique geographical location. The superiority of the geographical location is mainly reflected in the natural barriers in the geographical environment. The most famous of them is Hangu Pass. These dangerous passes are located at the transportation hub on the southeast and southeast sides of Guanzhong. They are what military strategists call easy to defend but difficult to attack. land.
In addition to the influence of the geographical environment, there is also the strong support of the economic foundation. In ancient China, the southeast coast south of the Yangtze River and the sea had not been fully developed, so the Yellow River Valley was still an important economic decisive factor. Chang'an is located hundreds of miles away from the Weihe River Plain. It not only has sufficient food, but also has a large population.
What’s interesting is that although Chang’an was good, after the prosperity of the Tang Dynasty, it collapsed like a jade tree in the backyard. Let’s talk about the geographical environment first. Qinling Mountains is far superior to Guanzhong. Then let’s talk about the economy and population. After the economic center of gravity moved south, the warm and fertile soil in the south has been developed, and the cooked food that takes more than a year has surpassed several streets in the Weihe Plain.
Secondly, there is a mainstream view on the decline of Chang'an, which is very thought-provoking even in today's society. This is a large-scale destruction of the environment. According to statistics, Chang'an's ecological environment experienced significant deterioration in the decades before and after the Tang Dynasty, and the forest coverage rate dropped again and again, eventually forming the current pattern of the Loess Plateau. Environmental damage caused a decline in soil fertility, resulting in food shortages and economic bankruptcy. It seems that Chang'an's decline is expected.