[1] In southern Boiotia, central Greece; site of a Greek victory in the Persian War, 479 BCE. See also pi 1701; OCD4 s.v. Plataea. (The Suda's accentuation of the headword here on the final syllable is odd, and probably mistaken. The normal singular toponym was *pla/taia -- though in fact plural *plataiai/ is more commonly found.)
[2] Evidently quoted from somewhere; perhaps Homer, Iliad 2.504, though there are many other possibilities.