This is an interesting topic. Ranger Chiron, I believe you are referring to the Sacred Band of Thebes. The Sacred Band was the most respected and feared group of elite soldiers of their day, and in fact defeated the Spartans in battle. They were professional soldiers, and very highly trained.Chiron wrote: One Kingdom that was called Theves was known for them and had good fighters. But the Spartans were NOT. That is a myth that jealousy may have brought.
What's remarkable about the Sacred Band is that the 300-man strong unit was always composed of 150 homosexual couples. I quote from a book I just finished reading: "The theory within this organization was that the desire to protect and impress one's lover would bring out the best fighting spirit in each soldier. No one would dishonor himself or his partner by fleeing the battle and bringing shame upon them both. Therefore, the unit would remain close-knit, as each soldier acted not only for himself but also his partner, as well as for the unity and army as a whole."
After a few decades of existence, the unit was annihilated to the last man by the superior manpower and tactics of Philip II.
If anyone is interested, here is a link to the book:
100 Decisive Battles
The author is a little dry, but the content is excellent.