Mountains and the sea caused Greek centers of population to be cut off from one another. As a result, separate city-states developed, each with its own form of government and system of laws. In Greek, the word for city-state was polis.
At the same time, Greeks also shared in a common culture, based on their language, religious beliefs, traditions, and close economic ties. For example, all Greeks believed in the same gods and goddesses, including Zeus, Athena, and Apollo, who were believed to live on Mount Olympus. Their myths, such as the story of Jason and the Golden Fleece, and the siege of Troy, still thrill us today. Citizens from all the Greek city-states participated every four years in Olympic games in honor of Zeus and the other Greek gods. The Greeks believed their gods were pleased by strong, graceful human bodies.