Comparative studies of the Roman and Han empires

Historians have engaged in historical comparative research involving the roughly contemporaneous Roman Empire and the Han dynasty of early imperial China. At their peaks, both states controlled up to a half of the world population and produced political and cultural legacies that endure to the modern era; comparative studies largely focus on their similar universal scale at their pinnacles and on synchronism in their rise and decline.

The vast majority of studies focus on one or the other but the comparison of the two has attracted interest in the 21st century. Of all comparative history, most popular seems to David Engels' research comparing the advent of the Qin and the Han dynasties with the ascension of imperial Rome, though it is probably second to the comparison between Rome and the United States. Studies examine the patterns of ethnicity, identity, the views of foreigners, and geopolitics. Scholars also explore the relevance of ancient structures and characteristics to China's loss of world leadership in what has been called the Early Modern "Great Divergence".