Kublai Khan sent Nicolo and Maffeo Polo as his ambassadors to the Pope. His message ran: "You shall go to your High Priest and shall pray to him on our behalf to send me a hundred men skilled in your religion. ... and so I shall be baptised, and, when I shall be baptised, all my barons and great men will be baptised, and then their subjects will receive baptism, and so there will be more Christians here than in your parts."
The whole East was being offered to Christ. Yet the Pope did nothing. In 1289 Pope Nicholas the Fourth did send missionaries, but they were far too late and far too few and so the chance was lost.
How different history and world politics might be today if all China and the East had been gathered in for Christ!