It was made up of many city-states led by Athens and Sparta. But despite its fragmentation, it's made innumerable contributions to not just Western civilization, but civilization as a whole. And those are contributions in terms of forms of governance, like democracy, contributions in medicine, contributions in the arts, in mathematics, in the sciences. But perhaps their most famous contribution is in terms of philosophy. And if you're going to talk about philosophy in ancient Greece, the most famous three philosophers are Socrates, Plato, and Aristotle. Now before we get into the first of them, and really the teacher of Plato, who was then the teacher of Aristotle, let's get a little bit of context on this time period. So as we enter into the fifth century BCE, a couple of things are emerging.