Damn! The Mongols were Bad-asses: A Letter Sent to the Mamaluk Sultan in 1260 AD

Now this is how you write a threat.

From the King of Kings of the East and West, the Great Khan. To Qutuz the Mamluk, who fled to escape our swords. You should think of what happened to other countries and submit to us. You have heard how we have conquered a vast empire and have purified the earth of the disorders that tainted it. We have conquered vast areas, massacring all the people. You cannot escape from the terror of our armies. Where can you flee? What road will you use to escape us? Our horses are swift, our arrows sharp, our swords like thunderbolts, our hearts as hard as the mountains, our soldiers as numerous as the sand. Fortresses will not detain us, nor armies stop us. Your prayers to God will not avail against us. We are not moved by tears nor touched by lamentations. Only those who beg our protection will be safe. Hasten your reply before the fire of war is kindled. Resist and you will suffer the most terrible catastrophes. We will shatter your mosques and reveal the weakness of your God and then will kill your children and your old men together. At present you are the only enemy against whom we have to march.

Qutuz wasn't a slouch either. His reply was to kill the messengers and have their heads displayed on a gate to Cairo. People didn't fool around in those days.