Can’t blame the Spartans for holding a grudge

Wikipedia page

Basically Ephialtes was the guy who betrayed Leonidas's coalition of Greeks to the Persians at the Battle of Thermopylae. Unsurprisingly, he had a bounty placed on his head afterwards. Ten years later, Ephialtes is killed by someone named Athenades for an apparently unrelated reason, but the Spartans awarded him the bounty anyway.

Inspired by u/Nero2t2 's post