The Northern Zhou Dynasty, strategically based in the basin of the Wei River, is supreme in Northern China.

In the south, only the Chen Dynasty remains a rival.

Emperor Xuan, intending to conquer the Chen Dynasty in summer 580, sends Yang Jian to be the commandant at Yang Province (roughly modern Lu'an, Anhui) to prepare for the campaign.

Before Yang Jian can depart, however, Emperor Xuan suddenly grows seriously ill. Two of Emperor Xuan's close associates, Liu Fang and Zheng Yi, who are friends of Yang's, summon Yang to the palace to prepare to serve as regent, overriding the desire of another close associate, Yan Zhiyi, to appoint as regent Emperor Xuan's uncle Yuwen Zhao, the Prince of Zhao.

Emperor Xuan soon dies, and Zheng and Liu issue an edict in Emperor Xuan's name appointing Yang regent.

Yang immediately pleases the officials at the capital by abolishing the wastefulness and cruel policies of Emperor Xuan, and he himself demonstrates both hard work and frugality, which impresses the people.

Fearful of the intentions of the general Yuchi Jiong, the commandant at Xiang Province (roughly modern Handan, Hebei), he summons Yuchi back to the capital.

Yuchi, however, refuses, and believing that Yang's intentions are to usurp the throne, rises at Xiang Province against Yang.

He is supported by the generals Sima Xiaonan), the commandant at Xun Province (roughly modern Xiaogan, Hubei) and Wang Qian, the commandant at Yi Province (roughly modern Chengdu, Sichuan).

However, just sixrty-eight days after Yuchi rises in rebellion, the general Wei Xiaokuan defeats Yuchi, and Yuchi commits suicide.

Wang is also soon defeated, and Sima flees to Chen.

To prevent Yuchi's headquarters at Yecheng to be used again as a base of opposition against him, Yang Jian has Yecheng (Northern Qi's old capital) torn down.

During Yuchi's campaign, Yuwen Zhao makes an attempt to assassinate Yang, but fails.

In response, Yang puts Yuwen Zhao and his brother Yuwen Sheng, the Prince of Yue, to death, and after Yuchi is defeated, he begins to slaughter the Yuwen clan in earnest.

He also has Emperor Jing promote his titles quickly, and he changes his surname back to Yang.

Yang Jian conquers the Northern Zhou (Chou) and Zhen (Ch'en) dynasties, uniting China for the first time in almost four centuries.

He executes the last ruler Jing Di, age eight, along with fifty-eight royal relatives at Chang'an.

He proclaims himself emperor the first emperor of China’s Sui Dynasty, ruling from his capital at Daxian (Ta-hsing) (later Chang'an; Ch'ang-an).

The Sui Period sees order reestablished in China.

Sui Wen Di directs several large construction projects, such as the repair of the Great Wall and a canal system linking the fertile central region with the northern plain.

The Sui dynasty reintroduces civil service examinations according to the Confucianist philosophy.