It's good to be the king... except when you're an Aztec king at the time of the Spanish conquest of Mexico. While the Spanish were besieging Mexico City the previous king, Cuitlahuac, died of smallpox, along with a sizable proportion of the population. Cuauhtémoc took power as one of the few captains left eligible for the job (he was Moctezuma II's son in law). When he went to call for reinforcements from a neighbouring people, he fell into the hands of the Spanish, namely Hernán Cortés, offering him his knife and asking to be killed.
Cortés experienced an uncharacteristic bout of chivalry, declaring pompously that "a Spaniard knows how to respect valor even in an enemy". He respected Cuauhtémoc's valor until the royal treasurer pointed out that the brave Aztec might know the whereabouts of hidden treasure. As always, the idea of gold drove out all other ideals, and Cuauhtémoc was tortured by having his feet put to a fire. He stood up under the ordeal, perhaps because he was a brave Aztec but perhaps also because the Spanish notion of mountains of Aztec gold was largely a fantasy.
Cortés kept Cuauhtémoc around for a while, possibly hoping he would suddenly develop some expertise on finding hiding places for gold, but in 1525 two men told Cortés that Cuauhtémoc was conspiring to kill him. Cortés had Cuauhtémoc and two other Aztec lords hanged. When Cuauhtémoc learned of his sentence, he said the following to Cortés (as recorded by a conquistador serving under Cortés):
"Oh Malinche [Cortés]! Now I understand your false promises and the kind of death you have had in store for me. For you are killing me unjustly. May God demand justice from you, as it was taken from me when I entrusted myself to you in my city of Mexico!"
The same conquistador reports that Cortés suffered from a guilty conscience afterwards, being unable to sleep and injuring himself badly while wandering around at night.