How do you rule a continent? With paper, horses, and pass-tablets you can carry.

From 1206 to 1368, the Mongols built a logistics state: relay stations with fresh mounts, sealed edicts that crossed languages, state-merchant partnerships that kept goods and credit moving, and money that worked across borders. Envoys and artisans crossed Eurasia on schedules; friars debated at Karakorum; a monk from North China, Rabban Bar Sauma, made his case in Rome and Paris. Then climate shocks and plague rode the same routes, and unity fractured into four khanates. What endured were the tools: Ming canals and post, Muscovite courier roads, Mamluk frontier craft, Timur's method.

Drawn from chronicles, coins, seals, letters, and archaeology?this is how the Mongol century made distance usable, at a price.