When it comes to Lake Baikal, we naturally think of the place where Su Wu shepherded sheep in the Han Dynasty, which was called the Beihai Sea during the Han Dynasty, in fact, it is not an exaggeration to say that it is a sea, because it is indeed large enough, and the total water storage is more than 10 times the current water storage of all lakes in China. The key point is still the freshwater lake, which can be drunk directly, and the deepest depth reaches more than 1,600 meters, which is about the same as the sea. So we often wonder how good it would be for such a large freshwater lake to belong to China!
Our Chinese's record of Beijianger Lake began in the Han Dynasty, in 119 BC, Emperor Wu of Han sent Wei Qing and Huo Qubing each led 50,000 troops to Mobei, preparing to destroy the main force of the Xiongnu, and finally defeated the Xiongnu, Xiongnu's Shan Yu has been fleeing north, Huo Qubing led the army to pursue until today's Mongolia, once as far as Lake Baikal. This is the farthest place where the Chinese nation conquered to the north by force, but Huo Qubing did not actually control this place, and returned to the dynasty after the fight, so this could not be regarded as Chinese territory at that time.
Many years later, a messenger of the Han Dynasty named Su Wu, when he was on an envoy to the Western Regions, he was accidentally captured by the Huns, and the Huns said that you surrender, let you eat and drink spicy, and marry you a beautiful daughter-in-law. Su Wuning died and did not surrender, and the Xiongnu's Shan Yu said, if you don't surrender, you will be sent to Beihai to shepherd sheep, and you can go back when the ram gives birth. Su Wu stayed in Beihai for 19 years, and this Beihai is today's Lake Baikal, so at that time, Lake Baikal was the territory of the Huns, but according to the modern definition of the country, it did not belong to the Huns, at most it was control, because the nomads lived in no fixed place and did not have a fixed city, so for a long time in history, it did not belong to anyone.
In the Eastern Han Dynasty, the Xianbei people rose up and controlled the entire Mongolian steppe, and the Xiongnu part was integrated into the Xianbei people, and then the Turks controlled the northern plateau, but these nomads all have one thing in common, that is, they don't want to stay in this bitter cold place in the north at all, and they all want to go south to the Central Plains, not to mention Lake Baikal in the north. So Lake Baikal was too cold for ancient times, and it was worthless to occupy it, so for a long time in history it was ternullius.
It was different in the Tang Dynasty, because the powerful Tang Dynasty dealt the most ruthless and thorough blow to the nomads in the north. After the Tang Dynasty destroyed the Eastern Turks in 630 AD, the Tang Dynasty set up six prefectures in the north, covering the entire territory of present-day Mongolia and the area around Lake Baikal. Although the Tang Dynasty did not actually participate in the management, it belonged to the Tang Dynasty de jure because the Tang Dynasty's army had a firm grip on the place. Soon, the Anshi Rebellion occurred in the Tang Dynasty, and these northern governors gradually lost control. In this way, Lake Baikal has only been in the territory of the Tang Dynasty for 100 years, and it can only be regarded as controlled in the real sense of the word in the Mengyuan period.
During the period of Kublai Khan, Lake Baikal belonged to a northern province, after the fall of the Yuan Dynasty, the forces of the Northern Yuan Dynasty still controlled Lake Baikal, although the Ming Dynasty made several northern expeditions, but did not succeed in touching the Mongolian Plateau.
In the Qing Dynasty, before the Manchus entered the customs, the Manchus had firmly controlled Lake Baikal, but after the Manchus entered the customs and went south, they no longer paid attention to the management of Baikal. In the Kangxi period, a battle of Yaksa broke out between the Qing Dynasty and Tsarist Russia, and the two sides gave the border for the first time, and Lake Baikal was drawn to the **, which has been until today.
If we look back at the entire history of China, it was only the Tang Dynasty that really included Lake Baikal in the Chinese territory for the first time, and the Han Dynasty could only be regarded as a contact. Lake Baikal was controlled by northern nomads for most of the time, and later the Yuan and Qing dynasties controlled Baikal, but not for a long time, so Baikal did belong to China for a short time in the whole history of China.