The power of love might be the go-to magical gimmick used by the Care Bears to deus ex machina their way out of trouble, but back in ancient Greece, love was a powerful force used by Thebes to kick some serious butt.
The Sacred Band was an elite unit in the Theban army compromised of 150 pairs of homosexual lovers. As the Greek writer Plutarch explained it, the idea behind the Sacred Band was that soldiers would fight harder and fiercer if they knew that they were protecting a person they loved. The fact that everyone wants to look cool in front of their SO probably also helped. Specifically, it helped the Sacred Band defeat the Spartan army on two occasions in the fourth century B.C. Or to put it another way, the army made famous for the heroic actions of 300 of their soldiers was TWICE beaten at their own game by Thebes, a fact which they definitely would’ve rubbed in Sparta’s face in their Christmas cards if Christmas had been invented back then.
However, every good thing must come to an end, and the Sacred Band was eventually destroyed by Alexander the Great’s dad after the Thebans chose to die with their loved ones instead of surrendering, preemptively proving that “Don’t Ask, Don’t Tell” was and always will be utter bullcrap.