Postal Relay Station System

Timeline

1. -500–400Royal road from Persia to Anatolia · West AsiaThe Achaemenid Empire set up horse-change and reception stations along the royal road, and Herodotus recorded the speed of relay messengers; the Roman Empire's cursus publicus likewise maintained mutationes and mansiones along its highways, providing an early model for Eurasian relay systems.
2. 1081–1090Northern Song circuits and Islamic postal routes · ChinaNorthern Song maintained central and circuit-level relay and dispatch-post networks for imperial edicts and grain-transport documents; meanwhile the Islamic world's barid and horse-change stations still served communications between the caliph and provincial governors, with relay systems at both ends of Eurasia in mature operation by the late 11th century.
3. 1230–1400Postal route from Dadu to the Ilkhanate · Central AsiaThe Mongol yam relay stations integrated existing Chinese, Persian, and steppe routes, with stations for horse changes and travel by tally passes, creating for the first time a transcontinental unified postal framework across Eurasia; travelers such as Marco Polo all recorded its efficiency.