Which medieval travel account did the Franciscan William of Rubruck write after visiting the Mongol Empire?

The Journey of William of Rubruck is the medieval travel account William of Rubruck wrote after visiting the Mongol Empire.

William of Rubruck was a Flemish Franciscan missionary who traveled east between 1253 and 1255. King Louis IX of France sent him toward the Mongol court, where he met Möngke Khan at Karakorum. His route crossed Black Sea and Central Asian regions connected by Mongol imperial communications.

His report, traditionally titled the Itinerarium or Journey, contains detailed observations about Mongol customs, religions, geography, languages, and court life. It is one of the most valuable European eyewitness accounts of the Mongol world.

Rubruck’s account is sometimes confused with Marco Polo’s later travel narrative. Rubruck was a missionary and envoy, while Marco Polo traveled in the service of Kublai Khan and described a different period and route.