William of Rubruck
Soon after the Battle of Köse Dağ in 1243, the Empire of Trebizond surrendered to the Mongol Empire while the court of Nicaea put its fortresses in order. In the early 1250s, the Latin emperor of Constantinople Baldwin II sent an embassy to Mongolia in the person of the knight Baudoin de Hainaut, who, following his return, met in Constantinople with the departing William of Rubruck.