Pyrrhus of Epirus was an ambitious Greek king and a strong opponent against early Rome. In the Battle of Asculum in 279 BC, he triumphed against the Romans but destroyed most of his own forces.
In Pyrrhus’s own words, it was “a victory that is not worth winning because so much is lost to achieve it…If we are victorious in one more battle with the Romans, we shall be utterly ruined.”
This is now called a pyrrhic victory, where the deep losses outweigh the gain. Winning a battle, but losing the war.