When he discovers later that the Khan is planning to invade his homeland of the Song Dynasty, he renounces his loyalty to the Khan and flees from Mongolia to establishes a base of operations within one of Song's strategic strongholds; the city of Xiangyang.
He renounces his loyalty to the Khan. He flees from Mongolia. This is to establishes a base of operations within one of Song's strategic strongholds; the city of Xiangyang. The Khan is planning to invade his homeland of the Song Dynasty. He discovers later this.