Yam (Mongol Postal Relay System)

The Yam shows how a vast empire moved information and people at speed by staging resources ahead of demand. Stations were spaced roughly 25 to 65 km apart, and riders changing horses could reportedly cover 200 to 300 km a day. Access was controlled with the paiza, a tablet that entitled the bearer to fresh mounts and rations, and rulers restricted its issue when it was abused. Marco Polo described the system under Kublai Khan. Carriers follow the same principles today: capacity positioned in advance, controlled access, and hubs spaced so that most shipments move without waiting.

• Last MileFinal leg of delivery to the door
• Middle MileMoves between facilities before final delivery

• Cursus Publicuslate 1st century BCE to 6th century · Augustus sets up a state courier service with stations
• Persian Royal Roadc. 500 BCE · A relay highway from Susa to Sardis under Darius I
• Silk Road2nd century BCE to 15th century · Overland trade routes link China with the Mediterranean

1. Yam (route) en.wikipedia.org
2. Pax Mongolica britannica.com
3. Paiza en.wikipedia.org