Suzhou is a major prefecture-level city in southern Jiangsu province, China. As part of the Yangtze Delta megalopolis, it is a major economic center and focal point of trade and commerce. Founded in 514 BC, Suzhou rapidly grew in size by the Eastern Han dynasty, mostly due to emigration from northern China. From the 10th century onwards, it has been an important economic, cultural, and commercial center, as well as the largest non-capital city in the world, until it was overtaken by Shanghai.