A live-streamed Chinese language lesson under the sky—the ancients were taken aback.

Just as the two sides were facing off in front of the palace gates, the sky suddenly brightened.

Without any warning, the enormous screen of light unfolded above Xingqing Palace, piercing the stagnant air.

Everyone in the square stopped moving. The Imperial Guards' spears were still held horizontally in front of them, the people's fists were still clenched in front of their chests, and Old Zhang's cane was still suspended in mid-air.

They briefly forgot what they were doing, and simultaneously looked up at the sky.

"Hello everyone, I'm Yu Yan Bu Zhi. In the first three episodes, we followed Du Fu's poems and went through the entire process of the An Lushan Rebellion. In today's episode, we'll talk about the more profound impact of this catastrophe."

She paused slightly, her tone calm and restrained.

"As we said at the beginning, the An Lushan Rebellion was never just a rebellion; it was the watershed moment in the decline of the entire Chinese empire."

Understanding it will allow you to truly understand the trajectory of Chinese history over the next thousand years.

Why did the Five Dynasties and Ten Kingdoms period follow the Tang Dynasty?

Why was the Song Dynasty so wealthy yet so weak?

Why did the openness and inclusiveness of the Han and Tang dynasties turn into the introversion and conservatism of the Ming and Qing dynasties?

The answer lies in the An Lushan Rebellion.

In historical circles, there is a specific concept called the "Tang-Song Transition." Although the Tang and Song dynasties were only separated by the Five Dynasties and Ten Kingdoms period, which lasted for more than fifty years, the underlying logic of the two eras was completely different.

A reconstruction of Chang'an City appeared on the big screen.

"Let's look at Chang'an first. Before the An Lushan Rebellion, Chang'an was the largest city in the world at that time, with a population of over one million, and all countries came to pay tribute."

The camel bells of the Silk Road started from here and rang all the way to Rome.

However, after the An Lushan Rebellion, Chang'an became an isolated city.

Why? Because the Tibetans took advantage of the situation and invaded Hexi and Longyou, cutting off the vital passage of the Silk Road.

Chang'an lost all connection with the Western Regions from then on.

By the late Tang Dynasty, Chang'an was in ruins, and even the emperor fled several times.

Please note this change: starting from the An Lushan Rebellion, the political center of China shifted eastward, and Chang'an never regained its former glory.

Later dynasties, the Song Dynasty established its capital in Kaifeng, while the Yuan, Ming, and Qing Dynasties established their capitals in Beijing.

Chang'an thus exited the stage of history.

He couldn't stop talking and continued.

"Not only Chang'an, but the entire Yellow River basin never recovered from this."

The An Lushan Rebellion was mainly fought in the north, with the rebels and the imperial court locked in a protracted battle, resulting in burning, killing, looting, and destruction of fertile land, leading to a sharp decline in the population.

As we discussed in the last episode, in just five years, the registered population of the Tang Dynasty plummeted from 5300 million to less than 1700 million, a loss of nearly 3600 million people.

Most of these people were from the north, and the economic foundation of the north was completely destroyed.

A dynamic diagram showing the southward shift of China's economic center appeared on the screen.

"From then on, the imperial court's financial lifeline had to shift to the south of the Yangtze River."

The center of China's economy shifted south from the Yellow River basin to the Yangtze River basin, a shift that took a full thousand years.

In fact, this trend did not begin with the An Lushan Rebellion.

As early as after the Yongjia Rebellion and the Five Barbarian Invasions, a large number of northern gentry and common people fled to the south, and the economic center began to slowly shift southward.

However, the An Lushan Rebellion was a decisive blow, completely devastating the north and making the south the economic pillar of the empire.

Throughout the Song, Yuan, Ming, and Qing dynasties, and even to this day, the South has always been the economic center of China.

This格局 (structure/pattern) was established starting with the An Lushan Rebellion.

Li Longji's face turned pale. He couldn't believe it. He had created the Kaiyuan era of prosperity and built Chang'an into the largest city in the world, where all nations paid tribute and the city was ablaze with lights.

How could Chang'an have become like that after his death? He was the Emperor of Tang, the ruler of all nations. How could his Chang'an possibly disappear from the stage of history?

Then he heard the old man in the square speak again, his hoarse old voice hurling back the fear he had just suppressed.

"Are we just going to wait here to die? Did you hear what Tianmu said about what Chang'an will become in the future? A Chang'an that even the emperor doesn't want, a Chang'an that even the emperor can't stand, a Chang'an that even the emperor has fled from time to time!"

Li Longji suddenly lifted the beaded curtain and rushed to the railing in a few steps.

His fingers were gripping the railing tightly.

He doesn't believe it, he doesn't believe it!

He opened his mouth, wanting to shout "Deceitful words," wanting to shout "My Chang'an will last forever."

But he couldn't shout it out, and he didn't dare admit it either.

-

The person on the sky paused for a moment, then continued speaking with a somewhat reluctant tone.

"Emperor Yang of Sui suddenly gained more credit for his achievements nearly 150 years after his death."

Because the economy of the mid-to-late Tang Dynasty was entirely dependent on the Grand Canal, which was dug during the reign of Emperor Yang of Sui, it could almost be considered the "lifeline" of the mid-to-late Tang Dynasty.

The comments section was even more reluctant than the unspoken words.

How can we attribute the achievements of Emperor Yang of Sui to the common people?

The Tang Dynasty also benefited from the fortunes of the Sui Dynasty.

History is truly amazing.

……

"After the war, agriculture and water conservancy in the Guanzhong region were no longer sufficient to support the massive central government and Shence Army."

The Tibetan Empire in the northwest invaded and plundered the capital region year after year.

Almost every grain of rice and every bolt of silk for the Chang'an imperial court had to be transported from Jiangnan via the Grand Canal.

During the reign of Emperor Dezong of Tang, the Grand Canal's grain transport was cut off by regional military governors, and even the imperial guards in Chang'an ran out of food. When the canal was reopened, Emperor Dezong was overjoyed and shouted to the crown prince, "The rice has arrived in Shaanxi, and my son and I are alive!"

Nothing defines the meaning of "lifeline" better than the emperor's words.

Moreover, the canal not only supplied the central government but also allowed for control over the areas along its route.

By firmly controlling the regional military governors along the Grand Canal, the imperial court spatially isolated the separatist regional military governors in Hebei, preventing them from forming a unified force.

At the same time, the canal also served as a rapid transit route for the central government to conduct military mobilization.

It can be said that the Tang Dynasty's ability to repeatedly appease regional warlords while simultaneously experiencing a resurgence in its power stemmed from the Grand Canal's continuous supply of wealth and military manpower.

Li Shimin, standing beneath the sky, spoke, his voice carrying a complex emotion that was hard to define—a mixture of anger and mockery.

"When Emperor Yang of Sui built the Grand Canal, everyone cursed him as a tyrant. I also cursed him back then. But Tianmu said that after the An Lushan Rebellion, the Tang Dynasty was completely dependent on that Grand Canal. Every grain of rice of the Chang'an court had to be transported by that Grand Canal."

He could hardly believe this ironic fact.

Li Shimin closed his eyes briefly, then opened them again, revealing the sharp edge of the former emperor on horseback.

He was determined to change the problems Tianmu mentioned, no matter what obstacles he encountered. He would not allow the Tang Dynasty to fall to such a state again.

Li Shimin straightened up and looked around at the assembled officials in the hall.

"My lords, the heavens have laid bare the future for us. Chang'an will decline for more than a hundred years, and the Tang Dynasty will fall for nearly two hundred years. This time is enough for us to do many things."

I do not seek for my empire to last for a thousand generations; the heavens have already told me that no dynasty can last for a thousand generations.

But I must at least ensure it doesn't perish in such a pathetic manner.

He walked to the palace gate and looked out at Chang'an outside the palace city.

"Chang'an cannot become an isolated city." He seemed to be saying this to himself, or making a promise to the city he had built with his own hands. "I will not let it become an isolated city."