What is history: it is the echo of the past to the future, the reflection of the future on the past. - Hugo
In 755, An Lushan personally led his 200,000 rebel army directly to Luoyang, but at this time the Tang army was gradually defeated, and Tang Xuanzong Li Longji fled west with Yang Guifei and others. So where is Tang Jun at this time? Why did you let An Lushan's 20 rebel soldiers come to the city?
This has to start with the military service system of the Tang Dynasty.
It is said that in the early days of the establishment of the Tang Dynasty, the military system of the Southern and Northern Dynasties was continued. What kind of military service system is this? Roughly speaking, the officers and men at that time had to farm and practice in peacetime, but they did not have to pay taxes, and in wartime, they prepared their own weapons and went to the battlefield. This was very practical during the Southern and Northern Dynasties, when the princes were divided, each regime had a small territory, and the economy was still sluggish.
But in the Tang Dynasty, it was not applicable, why? The territory is too big, and once the army is dispatched, it is often impossible to return for a year and a half, so that the cultivated land in the hometown will be left unattended and gradually abandoned. So later in the middle of Tang Xuanzong, they invented a new system of military service, which was a system of ten knots.
This means to divide the world into ten major theaters, and the commander of each theater is the emissary of jiedushi.
Of course, it was impossible to oppose the central government with one emissary, but later in order to deal with the nomads, there was a situation in which a general and several emissaries of the festival appeared. At that time, An Lushan was also the envoy of the Three Towns Festival, which could be described as a super warlord. This section made it easy to control the rights of the general troops at first, but later, for the sake of the needs of the war, the central authorities gradually handed over to them the power of local financial expenditure and the right to appoint and dismiss personnel. In this way, an independent small kingdom was formed, and the emissaries were no longer completely obedient to the words of the central authorities.
At that time, the Tang Dynasty fought a long-term war with the Nanzhao State in the south, faced various ethnic minorities in the northeast, and faced the invincible Arab Empire in the west, which can be said to be a three-front battle, and their main forces were concentrated on the border line, and there were very few domestic troops. An Lushan was able to command more than 200,000 troops at that time, while the Central Army of the Tang Dynasty only had a mere 100,000 men.
In addition, the combat effectiveness of an army that fights every day and kicks the right foot every day is also incomparable.
At that time, the Tang Dynasty had been singing and dancing for more than 100 years, and the central army that was proud of it in the past had long become a flower shelf with no combat effectiveness. These central armies, made up of the sons of the nobility, were all about surviving seniority in the army in order to earn themselves a path of promotion. And the rebels of An Lushan, as an army that fights with the nomads every day, are naturally hundreds of times stronger than them.
Therefore, the rebels went all the way south, encountered almost no decent resistance, and easily took Luoyang, the eastern capital of the Tang Dynasty. At this time, the Tang Dynasty still had one only place to rely on, that is, to stick to Tongguan, but the result was that Li Longji was also messed up.
At that time, Gao Xianzhi, Feng Changqing and other famous generals advocated holding Tongguan to the death, waiting for the reinforcements of the Western Army, and then fighting with the rebels to the death. However, Chang'an City was very dependent on water transportation, and in order to open up the water grain transportation channel in Chang'an, Li Longji ordered the Tang army stationed at Tongguan to fight, but Gao Xianzhi and others did not agree, and were eventually ordered to be executed. Although Ge Shuhan, who was in charge of military affairs later, also knew that he could not fight, but under the pressure of Li Longji, he could only fight hard.
The final result was that the Tang army was defeated, the rebels occupied Tongguan, Chang'an City was in danger, and Li Longji ran away with his own woman. However, on the way out, the crown prince Li Heng launched a mutiny, Yang Yuhuan became a political victim, Li Longji lost his rights, and Li Heng continued to command the battle north, finally recapturing Chang'an and Luoyang in June and October 757.