During the last two centuries BCE, the Western Han capital of Chang'an, near today's Xi'an in northwest China, outshone Augustan Rome in several ways while administering comparable numbers of imperial subjects and equally vast territories. At its grandest, during the last fifty years or so before the collapse of the dynasty in 9 CE, Chang'an boasted imperial libraries with thousands of documents on bamboo and silk in a city nearly three times the size of Rome and nearly four times larger than Alexandria. Many reforms instituted in this capital in ate Western Han substantially shaped not...