What was the beginning of the Greek civilization that separated cities which had their own governments?

The beginning of Greek civilization is often traced back to the emergence of city-states, known as "poleis," around the 8th century BCE. Each polis, such as Athens, Sparta, and Corinth, operated independently with its own government, laws, and customs, fostering a distinct cultural identity. This decentralized structure encouraged political experimentation and civic participation, laying the foundation for democratic principles, especially in Athens. The competition and collaboration among these city-states significantly shaped Greek identity and its contributions to Western civilization.