Mongol Relay System (Jam)

Timeline

1. 1234Karakorum post road · MongoliaDuring Ögedei's reign, relay stations were widely established across the empire, with relay households required to raise horses and provide food and drink, greatly speeding military intelligence and edict transmission from the steppe to North China and Central Asia and laying the foundation for the later jam system.
2. 1264–1270Dadu–Central Plains post road · North ChinaAfter establishing his capital at Dadu, Kublai merged the Mongol örtöö with the relay systems left by the Jin and Song into the Yuan jam system, administered by the Bureau of Transmission and the Ministry of War's Bureau of Maps, with the Dadu–Kaiping–Central Plains trunk lines significantly densified in the 1260s.
3. 1271–1275Persia–Dadu post road · Silk RoadMarco Polo's travels describe holders of the emperor's tally receiving free horse changes, food, and lodging at imperial relay stations, reaching Dadu from Persia in several months—a primary corroborating source for studying 13th-century jam operations and Eurasian travel speeds.