Ghengis Khan, after he tried to start a trade empire and the local caliph first imprisoned, then beheaded, his ambassador. The head was then sent back to Ghengis in a sack.
Unfortunately, the murdered emissary was one of Ghengis' best friends. The Khan tore the non-Turkic Muslim world apart to avenge his murder (and who wouldn't???). By the way, it was the 12th century that the Muslims got stuck in (my typo), and most of the bad press we hear about Ghengis entered "Western history" from the viewpoint of the Muslims, from whom European scholars took information on the state of the rest of the world.
Oh, yes, I remember that incident being portrayed in a movie once, long ago.
Putting it in the 14th century made me think you were referring to the Il-Khans, or maybe Timur.
The Arabs eventually stopped the Mongol invasion at Ain Jalut ("Well of Goliath") in the Sinai, but I forget in what year. Too, that may have been Batu Khan or Nogai or one of the other grandsons. Liegnitz was later, in iirc 1251 or 1257 -- and that was one of the grandsons. Batu, I think. Up against German, Polish, and Hungarian knights, in the unfamiliar environs of deep forest. Both of them must have been hellacious battles.
But you're right, the Arabs were off center stage after about the 12th century, anyway. Saladin was a Kurd.