I hate to be Johnny Rain Cloud SunkenCiv, But the Sacred Band of Thebes, that Defeated the Spartans and Was Annihilated by Phillip of Macedon... was well.....
..I will let Plato Explain: "And if there were only some way of contriving that a state or an army should be made up of lovers and their beloved, they would be the very best governors of their own city, abstaining from all dishonour, and emulating one another in honour; and when fighting at each other's side, although a mere handful, they would overcome the world. For what lover would not choose rather to be seen by all mankind than by his beloved, either when abandoning his post or throwing away his arms? He would be ready to die a thousand deaths rather than endure this. Or who would desert his beloved or fail him in the hour of danger?"
Yeah, they were a bunch of homos as well (assuming the tale is correct; Plato's real name was Aristocles, but Socrates gave him the nickname Plato, which means "broad shoulders" or thereabouts, sounds fishy), but they didn't enslave their neighbors or have that top-to-bottom totalitarian, terrorist, slavery-based state.
When I first read about the Theban Sacred Band I thought “What, they had boyfriends and girlfriends fighting side by side?” I was young and naive.