In 1245 CE a letter from Pope Innocent IV travelled 7000km to Güyük Khan (Genghis’ grandson) demanding peace. The letter back from the Great Khan was… not friendly.
In the 13th century CE both the European Crusaders and the Mongol Empire were in sustained but separate conflicts with the Islamic caliphate. Despite being so far apart from each other, both geographically and philosophically, many attempts were made to set up some kind of alliance. They were not successful.
The first official contact between the two powers came from Pope Innocent IV. He sent a letter, now known as Cum non solum, to the leader of the Mongols. It’s pretty obvious that this letter predates any good understanding of intercultural communication, because it’s pretty darned rude.
You ought not accordingly take up the audacity of ravaging further, because, as the sword of your power rages against others, the all-powerful Lord has so far permitted diverse nations to be laid low before you; but He in our age frequently passes over chastening the proud until the right time, so that if they neglect to become humble of their own accord, He may not hesitate to punish their wickedness in time and may exact more serious retribution in the future.
Pope Innocent IV: a real diplomatic charmer. Anyway, this letter wended its way across Eurasia to the Mongolian capital Karakorum, arriving just in time for the election of Güyük Khan, the grandson of Genghis Khan. Here’s the problem: in translation, “peace” from the letter would have been understood as “subjugation” or “subjection” by Güyük Khan. So he wrote a letter back to the pope, which didn’t make it back to Rome until 1246:
You must say with a sincere heart: ‘We will be your subjects; we will give you our strength.’ You must in person come with your kings, all together, without exception, to render us service and pay us homage. Only then will we acknowledge your submission. And if you do not follow the order of God, and go against our orders, we will know you as our enemy.
Oh well, so much for an alliance.