Long before the modern ideal of religious pluralism, the Mongol Empire held together Christians, Muslims, Buddhists, and Taoists under a single rule — not by accident, but by deliberate policy. This episode explores how Genghis Khan and his successors, from Ögedei to Khubilai, exempted clergy from taxes, welcomed foreign missionaries at Karakorum, and built an imperial ideology that placed the Eternal Heaven above all gods. We look at the 1254 debate at Möngke's court, where Franciscan friar William of Rubruck watched Buddhists, Muslims, and Nestorian Christians argue theology while the Khan listened. We examine the yarghuchi courts that adjudicated interfaith disputes, the role of Buddhist monk Haiyun as Khubilai's advisor, and the eventual shift toward Tibetan Buddhism under the Yuan. And we ask: was Mongol tolerance genuine conviction, or just pragmatic empire management? The answer, as we'll see, shaped Eurasian history for centuries.