Don't ask don't tell...

... about the other 300:

Gorgidas,  according to some,  first formed the Sacred Band of three hundred chosen men,  to whom,  as being a guard for the citadel,  the State allowed provision,  and all things necessary for exercise:  and hence they were called the city band,  as citadels of old were usually called cities.  Others say that it was composed of young men attached to each other by personal affection,  and a pleasant saying of Pammenes is current,  that Homer's Nestor was not well skilled in ordering an army,  when he advised the Greeks to rank tribe and tribe,  and family and family together,  that- 
"So tribe might tribe,  and kinsmen kinsmen aid."
but that he should have joined lovers and their beloved.  For men of the same tribe or family little value one another when dangers press;  but a band cemented by friendship grounded upon love is never to be broken,  and invincible;  since the lovers,  ashamed to be base in sight of their beloved,  and the beloved before their lovers,  willingly rush into danger for the relief of one another.  Nor can that be wondered at since they have more regard for their absent lovers than for others present;  as in the instance of the man who, when his enemy was going to kill him,  earnestly requested him to run him through the breast,  that his lover might not blush to see him wounded in the back.  It is a tradition likewise that Iolaus,  who assisted Hercules in his labours and fought at his side,  was beloved of him;  and Aristotle observes that,  even in his time,  lovers plighted their faith at Iolaus's tomb.  It is likely,  therefore,  that this band was called sacred on this account;  as Plato calls a lover a divine friend.  It is stated that it was never beaten till the battle at Chaeronea:  and when Philip,  after the fight,  took a view of the slain, and came to the place where the three hundred that fought his phalanx lay dead together,  he wondered,  and understanding that it was the band of lovers,  he shed tears and said,  "Perish any man who suspects that these men either did or suffered anything that was base."

(From Plutarch,  Pelopidas,  in John Dryden's translation.  Minor correction:  archeologists excavating the tomb of the Sacred Band at Chaeronea found only 254 skeletons, so we can conclude some survived.  The great marble lion placed over the tomb by the battle's survivors still stands.)