Greeks lived in city-states, which consisted of a city and its surrounding area. Most of these city-states featured at least some form of slavery, and in all of them, citizenship was limited to males. Sorry, ladies. Also, each of these city-states had its own form of government, ranging from very democratic unless you were a woman or a slave, to completely dictatorial. And the people who lived in these cities considered themselves citizens of that city, not of anything that would ever be called Greece. At least until the Persian Wars. So between 490 and 480 BCE, the Persians made war on the Greek city-states.