From the Sixteen Kingdoms period of the Eastern Jin Dynasty into the Southern and Northern Dynasties period, when the North was the Northern Wei regime that unified the North, and in 534 the Northern Wei was divided into Eastern Wei and Western Wei. Subsequently, Eastern Wei was replaced by Northern Qi, and Western Wei was replaced by Northern Zhou. In 577, Northern Qi was destroyed by Northern Zhou, which unified the north. In 581, Yang Jian replaced the Northern Zhou dynasty to establish the Sui Dynasty, the Sui Dynasty, until the death of Sui In 618 AD, Li Yuan declared himself emperor and established the Tang Dynasty.
Emperor Xuan of Northern Zhou, Yuwen Yun, married Yang Jian's daughter and established him as the main palace, and was Yang Jian's son-in-law. One of the "Eight Pillar States" of Northern Zhou, the eldest daughter of Dugu Xin, the Duke of Weiguo of Northern Zhou, was empress dowager Yuwen Yu of northern Zhou Ming; the fourth daughter was Li Xun's wife Empress Zhenyuan, that is, Li Yuan's mother; the seventh daughter, Dugu Jialuo, was Yang Jianzhi's empress and the mother of Emperor Sui; Li Yuan's wife Dou was born to Princess Xiangyang, the sister of Emperor Yuwen Yong of Northern Zhou, that is, Emperor Wu's niece. In this way, Yang Jiansui formed a conjoined relationship with Emperor Yuwen Yu of the Ming Dynasty and Li Xun the Duke of Tang. Li Yuan became the niece and son-in-law of Emperor Wu of Northern Zhou, the nephew of Emperor Yang Jian of Sui, and the uncle and cousin of Emperor Yang Guang of Sui.
Emperor Wen of Sui carried out a series of reform measures, such as de-xianbei, changing the official system to a five-province and six-ministry system, abolishing the nine-pin Zhongzheng system into a examination system, and so on. Behind these seemingly uneventful moves are actually butcher knives against the Guanlong Gate Valve Group. To remove the Xianbei needle is to isolate the Xianbei gate valve group, the five provinces and six ministries system is to weaken the influence of the door valve forces on the government, and the examination system is to abolish the privileges of the door valve group and use the Xinshi class to oppose the door valve group. Including the construction of the Grand Canal by the Sui Dynasty Emperor, its political purpose was to move the economic center out of Guanzhong in order to get rid of the control of the Guanlong Gate Valve Group!
Since the Wei and Jin dynasties, the Chinese Mongol clans have been in charge, and they have married each other to form the upper and middle levels of society, controlling the government and economic privileges of the dynasty. In order to maintain their own dominance, political marriages between the Mongol clans abounded, forming a huge network of upper-class social relations.
The consolidation of power requires many political marriages, which also creates the so-called high-level blood relations, which penetrate each other. It can be said unceremoniously that if these emperors in the Northern Wei, Western Wei, Northern Zhou, Sui Dynasty, and early Tang Dynasty were more or less related by blood, it was only a matter of the distance of blood relations.