Separate City-States shared ideas, shared their "civilized" politics and arts, and freedom for expression arose from tolerance of differences, and embracing of them. Thus, we have (thanks to medieval monks' translating and transcribing), the Saga writer Homer, the playwright Sophocles, the philosophers Plato and Aristotle, and because of freedom of thought by these ancient greeks, we have a wondrous society that predates Christ by quite a few years. This also survived in Rome, luckily.
