The Great Khan seems to have had a particular hatred of Islam, even ordering his soldiers to kill the dogs in Muslim towns the Mongols had captured. Mosques were routinely razed and Buddhist temples built over them. He was, however, tolerant (even indulgent) of Christians- most likely due to having a Christian Mongolian wife (probably a Nestorian, as they missionized heavily as far as China).
His conception of the divine was Tengri, or Eternal Blue Heaven, and I've even read that he was a Christian convert, albeit privately. I doubt this since he was devoted to his Tengri worship and the Tibetan branch of Buddhism.
Marcadores