The Sui Dynasty (581–618) was a dynastic clan that ruled for 37 years over much of the region. The course of their empire was strangely reminiscent of the Qin Empire; the Mandate of Heaven seemed to come into play.
The Sui Empire started when the ruling clan conquered Nanjing in 589. Along with the Qin Dynasty, the Sui Dynasty was one of the two dynasties of shortest duration that ruled big empires in the region.
The Qin Dynasty had ruled much of the same region 800 years before though their great empire only lasted for 15 years.
As the Qin Dynasty did, the Sui Dynasty used the people to carry out huge construction projects and fight large-scale wars to invade other countries. Their Great Wall and Grand Canal ranked among the world's greatest feats of engineering at the time.
Their rule was harsh, and their dynasty ended in big rebellions also.
Perhaps the Sui rulers initiated their large-scale projects in an attempt to make their empire more secure since the region had a history of 500 years of large empires disappearing.
The Eastern Han Dynasty (25–220 AD) lasted for about 200 years. At its end, the Eastern Han Empire split into three warring states. That was called the Three Kingdoms Period.
Then in 376 AD, there were two large empires that divided the region north and south.
In 560, there were four kingdoms in the area. This was called the Southern and Northern Dynasties era (420–589).
One of the four kingdoms of this era was called the Northern Zhou. The Northern Zhou controlled a big inland region that reached from Mongolia and down into the southwest. It was far from the sea.
In 581, the Sui Dynasty began when a member of the ruling clan of Northern Zhou killed about 60 of his brothers and relatives and made himself the emperor of his kingdom.
He was called Emperor Wen. He wanted to strengthen his empire, so he gained the support of Confucian bureaucrats and expanded his army.
Emperor's Wen goal was to control the region. Do this this, he initiated large construction projects, installed Confucian bureaucrats, and initiated major wars.
The Chen Empire was to the southeast, and the big Yangtze River was a natural boundary.
It is said that Emperor Wen sent about 500,000 troops across the Yangtze River in 588. In 589, he conquered the Chen Empire capital called Jiankang that is now called Nanjing. This is how the Sui Empire began.
During his reign, he initiated construction projects involving millions of laborers reminiscent of the Emperor of the Qin. His major policies were spreading Buddhism, reinstituting rule by Confucian bureaucrats, and making the people poorer for his wars and construction projects.
Emperor Wen was a Buddhist and tried to spread Buddhism. Mahayana Buddhism had spread and became popular in the region in the various kingdoms during the preceding several hundreds of years.
The religion was taught by monks and others from Central Asia and by various kings and emperors starting from the Eastern Han era.
In the year 601, Emperor Wen expressed an edict that said:
“All the people within the four seas may, without exception, develop enlightenment and together cultivate fortunate karma, bringing it to pass that present existences will lead to happy future lives, that the sustained creation of good causation will carry us one and all up to wondrous enlightenment.”
During the Han era, educated Confucian bureaucrats ruled the Western Han Empire. Their influence waned in the Eastern Han Empire, and they didn't rule in the Northern Zhou state.
Emperor Wen followed the example of the Western Han Empire and placed Confucian literati into his administration of power.
He also wanted to develop the infrastructure. Two major projects were building the Grand Canal and rebuilding the Great Wall of the Qin Empire.
He made Luoyang his capital, and he started to build the Grand Canal to help develop his new capital. The canal made transportation to his capital much easier.
It is now the longest canal in the world, and like the Great Wall of the Qin Dynasty, millions were forced to work on it. The first stage of the construction was finished in 605. It is thought that maybe half of the laborers died from the hard labor and conditions.
Even before he became an emperor, he had the wall of his kingdom rebuilt. After he became an emperor, he rebuilt other sections of walls along his northern boundary.
Another of his goals was to conquer Vietnam. He sent an army south in 602 and captured Hanoi. As the army went further south, though they won battles, their troops died of tropical diseases.
After ruling his large empire for 15 years, he died in 604. It is thought that he may have been killed by his son.
His son came to power in the year 604. He was named Emperor Yang. He ruled for 14 years and continued his father's policies of installing a Confucian bureaucracy, making wars, and building major construction projects, but because he poured so much of the empire's resources into these projects, he exhausted his resources and the people rebelled.
He was more like the Qin Emperor than his father, and he was also known for expending a lot of money on luxuries.
Like the Qin Emperor, he too ordered construction of large construction projects. He started to rebuild the Great Wall. During his reign, millions of laborers were forced to extend a section that stretched into Inner Mongolia.
A major engineering achievement was finishing the construction of much of the Grand Canal from Hangzhou to Beijing. He urged his people to finish it quickly because he wanted to use it to transport resources for his war against Goguryeo, an ancient Korean kingdom.
Though building the canal impoverished his own empire, the relative ease of travel on it added to the Tang Empire's prosperity.
The canal extended from the merchant city of Hangzhou in the south, across the Yangtze River, and up to Luoyang that was the capital of the empire.
He used the Grand Canal to send large armies for his campaigns into the Korean Peninsula to invade Goguryeo. A costly expedition was said to involve about 1.5 million troops and thousands of ships.
It is said that large mounds of equipment and rations were captured by the Goguryeo troops. Altogether, there were about four campaigns, and the Goguryeo troops defeated them all. Many died in the severely cold winters.
There was a lot of discontent about the loss of life, the forced labor, and the heavy taxes. Various leaders led rebellions. Emperor Yang was assassinated in 618 by his advisers.
In the northern part of the empire, Li Yuan (李淵, 566–635) and his clan emerged as powerful rulers. After capturing Chang'an (now Xi'an), Li Yuan declared himself the Tang Emperor in the year 618.