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Tang dynasty

In 618, Li Yuan founded Tang dynasty, which is generally considered a golden age of Chinese civilization. Taiyuan expanded significantly during the Tang dynasty, partly because Taiyuan was the military base of the founding emperors Li Yuan and Li Shimin. As Li Shimin wrote in 619: "Taiyuan, the base of the imperial regime and the foundation of the state." (太原，王业所基，国之根本)

In 690, Wu Zetian set Taiyuan as the Northern Capital, (北 都; Běidū), one of the three capitals, along with Chang'an and Luoyang, as depicted in the poem by Li Bai: "The king of the heaven has three capitals, the Northern capital is one of them." (" 天王三京，北都居一 "). In 742 AD, Emperor Xuanzong of Tang changed its name further to Beijing (北京). During the Tang dynasty, the title Northern Capital to Taiyuan had been endowed or abolished multiple times.