Rome and China never met. The two largest empires of the ancient world existed simultaneously — the Han dynasty and the Roman principate overlapped for roughly two centuries — and the goods they produced circulated between them across thousands of kilometers of overland and maritime routes. But no Roman diplomat reached Chang’an, and no Han envoy arrived in Rome, and what each knew of the other was filtered through so many intermediaries that the images were almost entirely mythological. Rome called China Serica, the land of silk. China called Rome Daqin, the Great Qin, imagining it as a mirror-image empire on the far western edge of the world. The distance between them was too great and the intermediary interests too profitable for direct contact to develop.