Not only did the Mongol Empire facilitate long-distance commerce, but it also prompted diplomatic relationships from one end of Eurasia to the other. As their invasion of Russia spilled over into Eastern Europe, Mongol armies destroyed Polish, German, and Hungarian forces in 1241–1242 and seemed poised to march on Central and Western Europe. But the death of the Great Khan Ogodei required Mongol leaders to return to Mongolia, and Western Europe lacked adequate pasture for Mongol herds. Thus Western Europe was spared the trauma of conquest, but fearing the possible return of the Mongols, both the pope and European rulers dispatched delegations to the Mongol capital, mostly led by Franciscan friars. They hoped to learn something about Mongol intentions, to secure Mongol aid in the Christian crusade against Islam, and, if possible, to convert Mongols to Christianity.

These efforts were largely in vain, for no alliance or widespread conversion occurred. In fact, one of these missions came back with a letter for the pope from the Great Khan Guyuk, demanding that Europeans submit to him. “But if you should not believe our letters and the command of God nor hearken to our counsel,” he warned, “then we shall know for certain that you wish to have war. After that we do not know what will happen.”24 Perhaps the most important outcome of these diplomatic probings was the useful information about lands to the east that European missions brought back. Those reports contributed to a dawning European awareness of a wider world, and they have certainly provided later historians with much useful information about the Mongols. Somewhat later, in 1287, the il-khanate of Persia sought an alliance with European powers to take Jerusalem and crush the forces of Islam, but the Persian Mongols’ conversion to Islam soon put an end to any such anti-Muslim coalition.

Within the Mongol Empire itself, close relationships developed between the courts of Persia and China. They regularly exchanged ambassadors, shared intelligence information, fostered trade between their regions, and sent skilled workers back and forth. Thus political authorities all across Eurasia engaged in diplomatic relationships with one another to an unprecedented degree.