The Mongol Empire’s relay-post system was called the yam.
The yam connected stations across the Mongol Empire, where authorized travelers could obtain fresh horses, food, and lodging. This network helped officials, messengers, merchants, and envoys cross enormous distances more quickly and reliably than ordinary travelers.
Stations were positioned along major routes, including those linking China, Central Asia, Iran, and the Eurasian steppe. The system was especially important during the 13th and 14th centuries, when Mongol rule brought many overland trade routes under one political authority.
The yam was not the same as a caravanserai. A caravanserai primarily sheltered caravans, while a yam was an organized communications and transport network using relay stations and replacement animals. Its effectiveness helped the Mongol administration govern distant territories and encouraged movement along Silk Road corridors.