After completing the revision of the clan chronicles and listing the first Boling Cui family Cui Mingan as the third class, Li Shimin drove back to Chang'an from Luoyang.

Before leaving, he also deliberately turned to Xingyang Zheng's territory and walked around, Li Shimin's meaning is too obvious, Xingyang is east of Luoyang, and the road back to Chang'an is completely different, and last year to Taishan and from Mount Tai back to Luoyang have passed through Xingyang, there is no need to go again.

But now the emperor wants to go through this experience, and the meaning is self-evident, that is, to express a kind of dissatisfaction and deterrence to the Zheng family of Xingyang and several other families with the surname of Qiwang.

It is estimated that if it weren't for the Fan Yang Lu family, the Boling Cui family, the Qinghe Cui family, and the Zhao County Li family were not nearby, otherwise Li Shimin might have run to their land.

Li Shimin, who is surnamed Qiwang, also has a good impression of the Li family in Longxi and the Wang family in Taiyuan, both of which have supported their father and son in the establishment of the Tang Dynasty, and the Lu family, the Cui family, and the Zheng family are not the same.

After going to Xingyang for a while, Li Shimin did not meet any of the Zheng clansmen, so he was so arrogant and smuggled around on other people's territory and then began to return home.

Luoyang, who left on the fifth day of the second month, was in Hebei County on the 13th, this place has nothing to do with the provinces of later generations, this place belongs to Hedong County, but it is the same as the name of the province in later generations, because it is located north of the Yellow River.

If you want to talk about the specific location, it is almost the Yuncheng Pinglu on the opposite side of Sanmenxia in later generations.

When he got here, Li Shimin didn't see any other beautiful scenery, so he took a boat to take a good look at Pillar Mountain.

The pillar mountain may not be obvious in later generations, but in ancient times it was famous, and the Northern Wei Dynasty Li Daoyuan's "Water Jing Note" contained: "The pillar is also the name of the mountain." Pen & fun & pavilion www.biquge.info Yu in the past to control the flood, the mountain when the water chisel it, so the mountain is broken to pass the river. The water of the river flows, wrapping the mountain and passing by, and the mountain is seen in the water if the pillar is ran, so it is called the pillar. ”

Since the area occupied by the mountain is definitely not small, so when Dayu controlled the water, it was because this mountain blocked the course of the Yellow River to open the mountain, dig both sides of the mountain, and let the water of the Yellow River go around the mountain.

In later generations, there is a protruding stone in the river and it is embarrassing to call it Pillar Mountain, which is really ridiculous. The same is true of the pillar mountain of Sanmenxia.

Although it is really the original site of Pillar Mountain, but when the reservoir was built, the Pillar Mountain had already been blown up, leaving only a small stone block, and it would be submerged when the water level was high.

In ancient times, the pillar mountain was really the pillar mountain, not to mention the foot of the mountain, just up to the top of the peak there was almost the size of a basketball court.

There is a small Taoist temple built on it, and there is really a feeling of a blessed land of gods in the clouds.

Looking down, on both sides are the rough river water cascading down with the waves, and the crashing stone walls rumble.

This kind of momentum can make Yan Zi say that I try to follow the Jun Ji in the river, and the turtle is in the left to enter the mainstay.

And the idiom of the mainstay is also from this mountain, because of Yanzi's admonition.

"Leaning on the pillar, looking north at the Dragon Gate; The vast traces of Yu, the vast Changchun" took a good look at Li Shimin in the pillar mountain, and finally the poem Xing Dafa also wrote a short poem, and then consciously wrote it very well, and let Wei Zheng find someone to engrave it on the back of the pillar mountain.

After a day in this place, on the 15th, Li Shimin led the minister of civil and military affairs to worship the Yu Temple, and arrived at the Willow Valley two days later to watch the salt pond.

The salt pond is the Yuncheng salt lake in later generations, also called the solution pool.

Salt pond salt production is the most famous pond salt production area, and the importance of it can be understood without much explanation. Salt is something that no animal, including a human, can do without at any time.

The salt pond is the most important and largest salt-producing base in the history of the Central Plains for thousands of years. Historians say that it includes "nine points of salt in the world", and whoever can occupy this place means that whoever can control the lifeblood of the world. Therefore, whether it is the Qin and Han Kingdoms, the Jin Dynasty, the Northern and Southern Dynasties, the Sui and Tang Dynasties, each generation of emperors has to send heavy troops to guard here.

According to the "Zuo Biography", the reason why the Jin doctors decided to settle in this area was because the land was fertile and "close to salt".

The area around the salt pond is almost completely forbidden and not approached by ordinary people. And because in recent years, Datang has laid down several places, such as the Qinghai-Tibet Plateau, there are large and small saltwater lakes, salt is not lacking, but the huge territory on the grassland is different, and the demand for salt is very large.

First of all, the Han people and local herdsmen who migrated in the past need a lot of salt, and the demand for wool in the Central Plains is huge, and the cattle and sheep raised by the people on the grassland, especially the sheep, do not know how many times more, and these livestock also need a lot of salt.

In the later generations, Wu Yuanqing's family raised sheep, that doesn't mean that it will be over if you let it eat some grass every day, feed it a little salt regularly, their family also raised a sheep for him to pass the time to raise, and the salt consumes a lot, not to mention the sheep on the grassland who don't know whether there are hundreds of thousands or millions.

Of course, there is also salt production on the grassland, but the herdsmen on the grassland let them graze and dry salt or anything is not their specialty, and the salt on the grassland is far from enough to meet the demand.

Again, the development of commerce and trade, Xue Yantuo, Goguryeo and other places all buy salt from Datang, and the importance of salt ponds to Datang has increased many times.

Li Shimin and his ministers began to plan to build a forbidden wall around the salt pond.

Originally, the forbidden wall was later built around the pool. If you don't rely on the garrison to patrol alone, you can't prevent it, you can't prevent it, not only may those who sell smuggled salt smuggle salt and sell it to hostile countries, but it will also greatly damage the income of the imperial court's salt tax.

Therefore, the original time and space is from the beginning of the Tang Dynasty to build the forbidden wall, the Song Dynasty continued to build, the Ming Dynasty continued to repair, after more than 1,000 years, "the end of the salt pond for a week, like a city", the total length of more than 100 miles.

Li Shimin's plan to repair the forbidden wall is just going down the original path. Because he attaches great importance to Yanchi, Li Shimin stayed here for three days before leaving for Puzhou.

Puzhou, Sima Qian called it "in the middle of the world" in the "Historical Records". Puzhou City is said to be the imperial capital of Yao Shun Yu Li Shun Puban was built here. "Imperial Century" cloud "Yao used to be in Pu, and Shun was in Puban." “

Puzhou is one of the most important cities in the north, not only dating back to ancient times, but also very famous in later generations.

The famous Yellow River Iron Ox learned in primary school textbooks was unearthed here, and the story of Zhang Sheng Cui Yingying also originated here.