Yes, there was quite a lot. By the time the Mongols arrived in the Near East, the crusaders were a very marginal community confined to a few cities along the Mediterranean coast. Still, the crusaders hoped that the Mongols would be the key to helping them reconquer the Holy Land, and there were attempts to make alliances and to fight battles together. The Pope and some European kings sent ambassadors and missionaries to negotiate with the Mongols, but their relationship was never very good. In the end this all came to nothing, but the Mongols and crusaders knew each other very well.
During the Fifth Crusade it was believed that some sort of Christian king from “the east” would be coming to help them defeat Islam:
“In 1217 Jacques de Vitry expressed hope that ‘the numerous Christian monarchs who dwell in the East as far as the territory of Prester John’ would aid the crusaders by attacking the Muslims. Consequently, when in 1221 the crusading leaders heard fresh rumours of operations against the eastern Muslims by an allegedly Christian army, they too were easily persuaded to link them with Prester John.” (Peter Jackson, The Mongols and the West, Routledge, 2005, pg. 21)
It’s not really clear where this legend comes from or why the crusaders believed in it so strongly, but they had been hoping for Prester John’s imminent arrival since the mid-12th century at least. Jacques de Vitry was the Bishop of Acre and was repeating news he heard during the Fifth Crusade. Clearly it at this point in the early 13th century they had heard rumours about Genghis Khan, although obviously they had no idea who he was or even where he was.
The reason they assumed there was a Christian army out there was because they knew they were other non-Latin Christians further east. Oriental Orthodox Christians had always lived in the Kingdom of Jerusalem and the other crusader states. The ones who lived further east in Asia were known to the crusaders as “Nestorians”, although that term is extremely vague and not very useful. But it was true that some Mongols were that type of Christian, so all that got wrapped up in the idea that there was a big Christian army coming west.
There was no actual contact with the Mongols until after Genghis Khan died in 1227. There were various Mongol factions, including the territory in central Asia/Persia/Mesopotamia (which eventually became the Ilkhanate), and the Golden Horde, which invaded Russia, Poland, and Hungary from 1236-1241. The Golden Horde stopped in 1241 and went home, possibly because Genghis’ son Ogodei died in 1241, but they had surprisingly and terrifyingly reached Europe itself and now Europe had to deal with them somehow. (They actually continued to rule Russia for several centuries.)
In 1245, a new pope, Innocent IV, was elected, and one of his first actions was to send some missions to the Mongols. The ambassadors met with the new Khan, Ogodei’s successor Guyuk, at Karakorum in 1246, and brought letters from the Pope explaining the basic tenets of Christianity and encouraging him to convert. Guyuk was not a big fan of this. His response was:
“Thou thyself, at the head of all the Princes, come at once to serve and wait upon us! At that time I shall recognize your submission.” (S.J. Allen, Emilie Amt, eds., The Crusades: A Reader, Second Edition, University of Toronto Press, 2014, pg. 369)
So diplomatically, things did not go so well… Meanwhile the Mongols in Persia were expanding westward as well, and came into contact with crusaders from Europe. In 1244 Jerusalem was sacked by the Khwarizmian Turks, refugees from central Asia whose kingdom had been destroyed by the Mongols. The Khwarizmians also defeated the Kingdom of Jerusalem at the Battle of Forbie later that year. So the crusader states were familiar with the Mongols, indirectly. The subsequent Seventh Crusade, led by Louis IX of France, didn’t accomplish much, but Louis sent some envoys and letters to the Khan to discuss an alliance. He had the same luck as Pope Innocent – the Khan was not interested, unless Louis submitted to the Mongols first.
Around this time, the Ilkhanate was formally established, and Hulegu Khan (a grandson of Genghis) destroyed Baghdad in 1258. The destruction of Baghdad may have been one of the most destructive events in all of history, certainly in the Middle Ages. The loss of culture and knowledge must have been immense. Shortly afterwards, Hulegu also encountered the crusader Principality of Antioch. The Prince of Antioch, Bohemond VI, knew what was good for him, unlike Innocent or Louis who didn’t have an actual Mongol army knocking at the gate. Bohemond happily, immediately, and totally submitted to the Mongols in 1260.
In 1260 Hulegu also conquered Damascus and Aleppo, effectively ending the Ayyubid dynasty (the dependents of Saladin). He wanted to conquer Mamluk Egypt as well, and the Kingdom of Jerusalem thought this would be a great opportunity to make an alliance with them, but the Mongols saw them as a minor player in the area, an annoyance more than anything. So the crusaders in Acre sat back and let the Mongols and Mamluks pound on each other. The Mamluks inflicted the Mongols’ first ever defeat, at the Battle of Ain Jalut in September 1260.
After Ain Jalut there wasn’t much contact between Europe and the Mongols, and the Mongols were largely absent from crusader territory in the Near East. One interesting attempt at forming an alliance came in 1271, when Prince Edward of England (the future Edward I) arrived on crusade and tried to coordinate an attack on the Mamluks, but that didn’t amount to much. The crusader presence on the mainland ended in 1291 when the Mamluks destroyed Acre, so there was no further crusader-Mongol contact after that…except, maybe, in 1300, when the Mongols briefly occupied Mamluk Syria and the crusader Kingdom of Cyprus may have been involved.
So, in summary: yes there was a great amount of diplomatic contact between the crusader states (Jerusalem/Acre, Antioch, and Cyprus) and the Mongols (both the Great Khan and the Ilkhanate), and there was also lots of diplomatic exchange between the Mongols and Europe, although it usually went very poorly. The Mongols had a huge impact on Middle Eastern politics when they sacked Baghdad and waged war against the Mamluks, but they considered the crusader states a minor ally at best and a nuisance at worst.
2. Jean Richard, La papauté et les missions d’Orient au moyen âge (Rome, 1977).
3. Reuven Amitai, Mongols and Mamluks: The Mamluk-Ilkhanid War, 1260–1281 (Cambridge University Press, 1995).
4. Antti Ruotala, Europeans and Mongols in the Middle of the Thirteenth Century (Helsinki, 2001)
5. Peter Jackson, The Mongols and the West (Routledge, 2005).
6. Written by u/WelfOnTheShelf.