Throughout history, empires have facilitated trade within their territories by building and securing trade and migration routes, and by imposing common norms, languages, religions, and legal systems, all of which led to the accumulation of imperial capital. This column, based on novel data on the rise and fall of empires over the last 5,000 years, shows that imperial capital has a positive effect on current trade beyond historical legacies such as sharing a language or a religion. This suggests a persistent and previously unexplored influence of long-gone empires on current trade.