The Cambridge Illustrated History of China

North and south China were reunited at the end of the sixth century under the short-lived Sui dynasty (581–617) and fashioned into an expansive, dynamic, cosmopolitan empire by its successor, the Tang dynasty (618–907). The reunification of north and south, the opening of the Grand Canal linking them, the creation of two huge capitals, and the expansion of interregional and international trade all stimulated economic growth. The Tang capital, Chang’an, grew to be the largest city in the world, housing perhaps a million people and attracting traders, students, and pilgrims from all over Asia. Especially before the massive Rebellion of An Lushan (755–63) brought to an end this era of expansion, the Chinese of the Tang showed themselves remarkably open to what other cultures had to offer. Music and art in particular absorbed considerable foreign influence, and Buddhism continued to be enriched by doctrines and rituals introduced from beyond Tang's borders.

Empire-building

The recreation of a huge Chinese empire in the late sixth century was not inevitable. By then the Chinese subcontinent had been divided into separate northern and southern states for over two centuries, each of which considered itself the true heir to the Zhou and Han dynasties. Given the geographical differences between north and south China, this situation might well have become a permanent one, like the division into eastern and western Roman empires in the West; the north and south could each have developed its own version of Chinese civilization.

However, the union of the north and south did occur, and the long-term consequences for Chinese civilization were profound. The centralized bureaucratic monarchy was refashioned on an even stronger basis than in the Han. This reunification and the resultant peace ushered in three centuries of cultural flowering. From then on those who thought about history had two examples from ‘modern’ times (the Han and Tang) that could be added to the three ancient dynasties (Xia, Shang, and Zhou) to prove the rightness of the unity of the Chinese world. Permanent division into independent states seemed less and less a natural, reasonable, or desirable state of affairs.