It's like this: In 5 18, Emperor Wendi of Sui Dynasty established the Sui Dynasty, with its capital in Chang 'an (now northwest of Xi 'an). In 582, Sui established Daxin Capital Daxing City in the southeast of Chang 'an City. In 583 AD, Sui moved its capital to Daxing City, but it was still customarily called Chang 'an. After Yang Di succeeded to the throne, Luoyang was regarded as Tokyo and later renamed as Du Dong. Emperor Yang Di and his courtiers were stationed in the East Capital, which became the actual capital.