But Lake Baikal was originally ruled by Xiongnu, and later Xiongnu and Zhongyuan were in a hostile state. It was not until the Tang Dynasty flourished that it attracted small neighboring countries to submit to the Tang Dynasty. At this time, the Tang Dynasty established a state to rule in the area where Lake Baikal was located, but most of the actual sovereignty was still in the hands of local tribes.
When the Tang Dynasty finally disintegrated, the Central Plains lost its jurisdiction over Lake Baikal, but the corresponding areas were always in the hands of Liao, Jin and the Mongolian Empire behind them. By the Ming Dynasty, although the rule of the Yuan Dynasty was overthrown, this area was not in the hands of the Ming Dynasty, the ruler of the Central Plains at that time. Later, the Qing dynasty defeated the remnants of Dayuan, thus taking over a ruling area such as Lake Baikal. So from the long history, Lake Baikal has been in the hands of the rulers of China since it was recorded in historical books.
After the Qing dynasty entered the customs, he devoted more energy to the rich place of the Central Plains. For the northern region, due to the lack of materials and the cold climate, we have not invested too much energy near Lake Baikal. At this time, Russia established its rule here by building a castle in the Far East and sending a few people. At this time, the Qing government was fighting other tribes, and Russia also attacked each other in the Qing Dynasty. For this reason, the Qing Dynasty signed a treaty with Russia, which included a part of Lake Baikal under Russian rule, and at the same time formally designated a northeast region as the Sino-Russian border.