I don't think they're applauding you
Here’s another one. Nickname, I mean. On St. Matthew’s Day, 1217, which is of course September 21 of that year, Kaupo the Accursed was killed in battle in Estonia. “The Accursed”. Dang. That’s gotta sting.
It might also interfere with recruiting to your cause. You go “Hey, we’ve got a big army, a great leader, a holy cause, who’s game to join in?” Then they go “OK, who’s this great leader person you have? Eh? Did you say ‘the Accursed’? Because maybe it’s just me but when you say that it sounds like it might not go so well.”
Now to be fair to the late Kaupo the Ill-Monickered, he probably picked up the name in the enemy camp, maybe even after the fact. He was apparently a leader of some Livonian group in the early 13th century, and is described in one chronicle as “quasi rex” which again isn’t quite the nickname you might have been fishing for. (It means “almost king” or “like a king” and isn’t nearly as cool or scary as “Tyrannosaurus rex” with no ifs, ands or quasis.)
Kaupo or Caupo (it matters less whether you spell it with a “k” or a “c” than whether you stick “the Akkursed” after it) was the first prominent Livonian to be christened. I know, I know, tallest building in Witchita. (Cue angry letters from Livonia.) Having gone to Rome and met Pope Innocent III, the same guy who sided with King John over Magna Carta boo hiss, he went home clutching the gift of a Bible to face a rebellion which he put down, then crusaded against some pagan Estonians related to his own quasi subjects… and died.
Apparently some people regard him as a fink and a traitor, others as a visionary who helped bring his people into Christian Europe. Personally I lean the second way, given the tragedies that have befallen the Baltic States in those periods when they were separated from the West. But Wikipedia says “Latvian legends, however, are unequivocal: there he is named “’Kaupo the accursed, the scourge of the Livs,... Kaupo who has sold his soul to the foreign bishops.’”
Even Antipope would be a step up. It would also help if your nickname was “guy who won the Battle of St. Matthew’s Day” not “guy who went under in it and good riddance”.
Even better to be called “Saint”, as in “the guy St. Matthew’s Day is named for”.
Kaupo the Accursed, not so much.