What was Jiangnan like in the Han Dynasty?

Jiangnan in the Han Dynasty was barbarian, because the commercial center of the Han Dynasty was in Chang 'an, which is now Xi 'an, and Shaanxi. At the end of the Eastern Han Dynasty, the three kingdoms occupied the south of the Yangtze River, and their commerce was a little prosperous. What really made Jiangnan prosperous was the opening of the Grand Canal by Emperor Yang Di of Sui Dynasty. Jiangnan was closer to the north and gradually prospered.