Yue was formerly called the Republic of Wuyue (吳越民國 / Wúyuè Mínguó). They continued to be called Wuyue until the Republic of China changed to the Republic of Wu. At that time, Wuyue dropped the "Wu" and became the Republic of Yue. To make matters more confusing, Yue's main language (and co-official with Mandarin) is Wu. Yue is part of the Chinese Union. Yue's largest city, Shanghai, is the most populous city in the world, and makes Yue a major player in world affairs (particularly economic affairs).