In 1260 the Egyptian Mameluke Sultan defeated a Mongol army in Syria in the pivotal battle of Ain Jalut. As a result, the principality of Antioch was destroyed and the kingdom of Cilician Armenia greatly weakened. WI: the Mongols had won the battle? Not all of the crusader states had supported the Mongols, but Bohemund VI of Antioch is a notable exception.
With the Mamelukes destroyed, the Mongols occupy Syria and Egypt with ease. What happens now?