This night, Li Tong temporarily stayed in Huangyuan City, refused the grand welcome banquet arranged by Duan Da, the assassin of Longzhou, and after a simple meal, in addition to the civil and military officials of Longyou, the rest of them, including those Hu chieftains in the state capital, were sent out together, and began to inquire about Longyou's military and political affairs and preparations for war.

As soon as he opened his mouth here, Duan Da, the assassin of Longzhou, got up and said: "I am derelict in my position, and I need to ask His Highness for my guilt." Previously, Xijing was in turmoil, and the news came to Longzhou, but he was powerless to help, wait and see the success or failure, and implore His Highness to surrender to the crime! ”

When Li Tong heard this, he was slightly stunned, along the way, he saw the governors of the prefectures and counties of Guannei Dao, and there were many excuses, but few people could directly admit their mistakes like Duan Da.

However, he made this trip to the west not to hold Xijing responsible, so he didn't plan to talk about it deeply, but before he could open his mouth to open the topic, Duan Da continued to speak, and after listening to the second half of Duan Da's words, Li Tong realized that Duan Da was not simply asking for guilt.

"But before His Highness sins, I beg that you may be excused to explain the reasons for the dereliction of duty. Longzhou is only a small state in the west of the country, thousands of households in the compilation, the land is the road of Longshan, the mountains and rivers are not rich, the things are not abundant, and the humble duty has been in the matter, diligent and diligent, so as not to lose.

However, at the beginning of the longevity year, the imperial court requisitioned and funded the march in Anxi, and the Longzhou land was on the side of the march, and the treasury was empty. The imperial court calmed down the great plan, and the lowly duty did not dare to discuss right and wrong, but I implore His Royal Highness to allow the children of Longzhou in Rongzhi to return to rest for a while, and the lowly duty is willing to accept the big crime! ”

Duan Dayan excused himself, but when the words came to this, there was already a lot of sadness in his demeanor, and he bowed to the ground in a low tone. The words are pleading, but in fact they are complaining.

As Duan Da made his statement, several civil affairs officials from various states present also stood up and opened their mouths to state, what they said was similar to Duan Da, and it was the destruction that the garrisons of the four towns of Anxi had brought to the people's livelihood in their respective states.

After Li Tong listened, he was a little silent for a while. He didn't think it was the governors of the states who had bullied him and put pressure on him, and he could feel similar hardships along the way.

The four towns of Anxi are far away from the Western Regions, and they are really far away from the Tang Dynasty. Under the conditions of transportation and transportation in ancient times, the cost of maintaining a large number of garrisons in the four towns for a long time can be imagined.

Even in the early period of Zhenguan and Gaozong, when the political situation of the Tang Dynasty was stable and the national strength was thriving, the four towns set up by the imperial court did not send a large number of people, and basically maintained a small number of elite garrisons, mainly to restrain Zhuhu and maintain order.

The Wu Zhou Dynasty was already indescribable, and the financial situation of the imperial court was already extremely bad, and even the maintenance of the 100 divisions in Beijing was quite simple. Under such circumstances, heavy troops must be stationed in Anxi, and the pressure can only be shared locally.

Today's four towns in Anxi, the size of the garrison is about 30,000 people, but the cost that needs to be borne is not only the consumption of money, food and materials for these 30,000 troops, but also the astonishing loss caused by traveling thousands of miles. The consumption of the latter is more than several times greater than that of the former, so the pressure borne by the Longbian states can be imagined.

At this time, not only the governors of the prefectures complained about their grievances, but even Meng Lingqing, the deputy envoy of the Heyuan Army, couldn't help but speak after listening to everyone's speeches: "Your Highness wants to ask about the situation of the armaments and wars in Longbian. When the old town of Yanguo Gong was Heyuan, there were advantages of opening canals and irrigating and raising troops in Tuntian, and Lou Xianggong succeeded him and grew stronger, so the Heyuan army also had a lot of reserves, but that was before.

After the recovery of the four towns, most of the grain was spent by Heyuan, and now, the Heyuan military warehouse is empty and barren. If there is no more subsidy, it may be difficult to maintain. The soldiers are poor and hungry, and it is difficult to fight. ”

Hearing that even Fu Meng Lingqing opened his mouth to express his dissatisfaction with the Anxi garrison, and said that the reserve situation of the Heyuan Army was so unoptimistic, Li Tong couldn't help but be slightly moved. The soldiers and civilians of Longyou were deeply troubled by the Anxi garrison, and he knew that this point must be treated and responded to carefully, otherwise the people's hearts would not be enough.

"Since Xianheng, the four towns have been frequently disturbed. The murderous country of Tibet, several times sent troops to the hometown of the ten surnames of the Western Turks, wanting to cut off my Tang Zhangye. In the old years, the Holy Emperor ruled the country, taking recuperation as the first priority, and temporarily promoted the four towns, but the result made the thieves even more rampant. Zhuhu is cowardly and cannot control Tibet. Therefore, the imperial court restored the four towns and diligently repaired the armor soldiers to stop the trend of poverty and evil in Tibet. This matter is urgent, there is no doubt about it! ”

In the face of the complaints of the masses, Li Tong first affirmed the strategic importance of the Anxi garrison, and at least he absolutely supported this arrangement.

Since the Qin and Han dynasties, the main border troubles of the Central Plains Dynasty have come from the north, whether it was the Xiongnu or the Turks during the Sui and Tang dynasties. The Hu people on the desert advanced and retreated calmly, and almost held all the initiative.

If we want to restrict their mobility and compress their activity space, we must find a way out in other aspects. Therefore, from the time of Emperor Wu of the Han Dynasty, he took the initiative to communicate with the Western Regions, the so-called Zhang Guo arm, in order to pass the Western Regions.

If it can't maintain enough influence in the Western Regions, then when facing the enemy coming from the desert, the Central Plains Dynasty will not have many choices to make, whether it is offensive or defensive.

Compared with the Qin and Han dynasties, the Tang Dynasty also had one more enemy on the plateau, Tubo, so the demand for control over the Western Regions was even higher. Once the Tibetans and Turks were allowed to get in touch through the Western Regions, then all the strategic initiative of the Tang Dynasty would be lost, and they could only be beaten passively.

Although Wu Zetian has been in power since he became a country, it is difficult to explain the truth in the foreign military aspect. But on the issue of the four towns of Anxi, Li Tong felt that he needed to say a fair word to his grandmother.

The Tang Dynasty conquered the Gaochang Kingdom during the Zhenguan period, set up the Anxi Protectorate for the first time, and built castles and military towns in Qiuci, Yanqi, Khotan, and Shule to maintain control and influence over the countries of the Western Regions, which is the origin of the four towns of Anxi. At that time, the main enemy faced by the four towns was still the Western Turks.

During the reign of Emperor Gaozong, the Tang army defeated the Western Turks Ashina Helu, and the Western Turks were officially destroyed, and the Tang Dynasty also established the sole hegemony in the Western Regions through the four towns of Anxi.

With the situation in the Western Regions under control and the Eastern and Western Turks destroyed, Gojong was able to concentrate all his efforts on waging a war against Goguryeo. At this time, after more than ten years of preparation, Lu Dongzan, the great minister of Tubo, led his army down the plateau and began to attack Tuyuhun, a subject of the Tang Dynasty.

At that time, all the forces of the Tang Dynasty were engaged in the war against Goguryeo, and there was no time to look west, after all, the power of Goguryeo was the grudge of the kings of the Sui and Tang dynasties. If Goguryeo is not destroyed, it cannot be called complete.

After three years of fighting, with the civil strife in Tuyuhun and the betrayal of the ministers to Tubo, Tuyuhun was defeated by Lu Dongzan. After that, Lu Dongzan personally sat in Tuyuhun's hometown and digested this victory.

The Tang Dynasty's war to defeat Goguryeo officially began in the Xianqing period and lasted until the Zongzhang period, which was the war that lasted from 660 to 668 AD.

At this time, Datang's national strength reached its highest point, and similarly, the people's power was also consumed to an extreme. After all, from the beginning of Gaozong's succession, he attacked and destroyed the Western Turks in the west and attacked Goguryeo in the east. Although the results of the war were brilliant, the consumption of the use of civil power also reached an astonishing level.

But there was not much time left for the Tang Dynasty to recuperate, and in 670, as the Tubo initially digested the Tuyuhun hometown, it once again showed its fangs, and in this year sent troops to capture the four towns of Anxi, and began to challenge the hegemony of the Tang Dynasty in the Western Regions.

The Tang Dynasty was naturally furious about this, and Gaozong immediately appointed Xue Rengui to lead an army to counterattack Tubo and escort the king of Tuyuhun back to his hometown. Not only to regain control of Tuyuhun, but also to give Tubo a head-on blow.

Xue Rengui acted as the general manager of the Luo Solo Road march, and Luo Tuo was the capital of Tubo, which shows that the Tang Dynasty's march was to attack the Tubo royal city as the highest goal. But the war that followed was the defeat of Dafeichuan, which countless military fans in later generations were worried about.

The defeat of Dafeichuan achieved the prestige of the son of Lu Dongzan as the military god of Qinling and Tubo, and it was also the first major defeat of the Tang Dynasty in the use of foreign troops. It must be known that in the fourth year of Xianqing, Su Dingfang not only attacked the Western Turks, but also let Tubo suffer a big defeat by the way.

But now, only ten years later, Tubo once again stepped down the plateau, and the Tang Dynasty's strong army, which had won a hundred battles, was defeated and lost. This is undoubtedly a major damage to the majesty of Datang.

There are many commentators on the defeat of Dafeichuan, but in the final analysis, Datang lost the battle in strategy, underestimated the speed of the rise of Tubo, and underestimated the importance of Tuyuhun to Tubo, and at the same time did not have a correct understanding of the loss of people's power caused by Datang's years of conquest.

In this battle, the Qinling army invested a total of 400,000 troops to participate in the battle, more than half of which were the people of the Tuyuhun Lost Country.

The Battle of Dafeichuan was the beginning of the struggle for hegemony between the Tang Dynasty and Tibet. Since then, in the past 20 years, the four towns of Anxi have changed hands several times, and the competition between the Tang Dynasty and Tubo for hegemony in the Western Regions has gradually become white-hot.

During the vertical arch years, in view of the situation of internal and external troubles, Wu Zetian temporarily gave up the four towns of Anxi, but soon Tubo's activities in the Western Regions became frequent, and Zhuhu in the Western Regions was not Tubo's opponent at all. Therefore, in the first year of longevity, after Wang Xiaojie recovered the four towns of Anxi, Wu Zetian decided to stay in the four towns with 30,000 heavy troops.

Since then, the four towns have reversed the previous state of frequent changes of ownership, and have been under the control of Datang. It was only after the Anshi Rebellion that Tubo took advantage of the weakness of the Tang Dynasty to send troops to seize the Hexi Corridor, but even so, the four towns still held out for decades.

Therefore, the strategic significance of the garrison of the four towns of Anxi cannot be weighed in terms of pros and cons.

If Wu Zetian had not made the decision to garrison the four towns after the recovery of the four towns, once the four towns fell again, even if the power struggle in the Tang Dynasty came to an end again in the Kaiyuan period, and when he returned to the Western Regions, he would have to face another Tuyuhun, and the Western Regions would have already become part of the hegemony of Tubo.