This chapter explains how the imperial urban system expanded into south China. After the fall of the Han Dynasty, fighting in the north caused southern migration, particularly after the An Lushan Rebellion in 755. This led to the growth of commercial cities in the Lower Yangzi Delta, which were linked to the northern capitals via the Grand Canal after the reunification of China under the Sui Dynasty. At the same time, Chinese cities were linked to the medieval international world over land along the Silk Road, and over sea via Guangzhou. In northern capitals, which reflected the influence of the Kaogongji, cities continued to be walled and divided into wards. However, in the Lower Yangzi Delta commercial cities were more open plan. Meanwhile, the arrival of Buddhism and Daoism into China brought monasteries and temples into cities, while monks began to take responsibility for aspects of urban governance along with imperial officials. Wards divided cities socially as well as physically. The wealthy enjoyed lavish lifestyles, built palaces and mansions, donated to monasteries, and constructed gardens. Goods and people from outside China made cities more cosmopolitan, and writers reflected on this and other aspects of urban life in their poetry.