Tom Holland has Miltiades shout "at them!" at the beginning of the battle of marathon. And in citations it's ascribed to a cetain "Aristides 3.566". Who is that ought to be? He also has an "Alcaeus 360" cite 3 pithy sayings of an "Aristodemus of Sparta". It can't be the dude who returned from the battle at Thermopylae, now, can it?
It's Plutarch's Aristides, although I'm not sure what Holland is referring to because I can't remember any such attribution to Miltiades in that work. Alcaeus was a lyric poet, a contemporary of Sappho's and a fellow Lesbian, whose works only survive in fragments: "Alcaeus 360" should properly be cited as "Alcaeus fr. 360," although it doesn't make much difference. The Aristodemus to whom the fragment attributes its sayings is an unidentified person, but considering that Alcaeus died sometime in the 6th Century it's unlikely to have been anyone involved in the Persian Wars, if such a person even existed in the first place and is not an invention of the poet's
Well Alcaeus was a Greek lyric poet who lived c. 600 BCE [EDIT: a letter], and one of his fragments in the Loeb edition is numbered 360. It is a not very nice maxim
Money is the man, and no poor man is good or honourable.
Other editions may have numbered the fragments differently. Does this sound like a maxim that would apply to the chapter in question?
I can't work out either of these references. My guess would be that the first was originally meant to read "Plutarch, Life of Aristides 5.3-4", as that is the passage describing the Battle of Marathon, though Plutarch does not cite Miltiades directly (nor does Herodotus, the better source for Marathon). As for the second, I have no idea. The only famous Alcaeus was Alcaeus of Mytilene, a poet long dead by the time of the Persian invasions. Aristodemus of Sparta practically has to be the dude who returned from the Battle of Thermopylae. He became a bit of a celebrity in Classical Greece for missing the final struggle at Thermopylae, suffering the punishment for cowardice at Sparta, and going berserk at Plataea to redeem himself, dying in the process. He may have had some apocryphal phrases attributed to him (though I cannot find any reference to them in Plutarch's Sayings of Lacedaemonians, which is our usual source for these).
If you're very keen to work out where he really got these things from, you could consider badgering Tom Holland in person on Twitter (@holland_tom). He is very active there and may well respond to your questions.