Them lets us define ourselves: us vs. Us could unravel what holds / defines us together. Peloponnesian war = greeks vs. greeks (climax of internal alterity) Panhellenism = united greece: all share same language (though different dialects), religion (though different local heroes, divine patron), ideals, common history (esp. Fades in and out throughout greek history (panhellenism as idea and ideal: prominent during foreign threat (persians, disappears upon resolution of foreign threat (creates anxieties b/c fighting old allies) Shifting relationships force greeks to realize that definitions of us and them are not set in stone. Different physis and nomos (national character, lifestyle respectively) b/w athenians and. Spartans (according to thucydides: makes war b/w the two inevitable. Herodotus >> tensions b/w athens and sparta during persian wars (divisions) Herodotus gave praise to both sides (athenians saved greece, spartans the best soldiers) during the persian war as well as outlining what makes them both different from each other.