Li Yuan defeated a Sui army at the Battle of Huoyi, opening the path to his capture of the Chinese imperial capital Chang'an and the eventual establishment of the Tang dynasty. Emperor Gaozu of Tang: Emperor Gaozu of Tang, personal name Li Yuan, courtesy name Shude, Xianbei name Daye Yuan, was the founding emperor of the Tang dynasty of China, reigning from 618 to 626 CE. Under the Sui dynasty, Li Yuan was the governor in the area of modern-day Shanxi, and was based in Taiyuan. September 8, 617. Wiki link