Ancient Greece developed along the Mediterranean coast and islands between 3000 BC to 30 BC. The civilization was never unified but shared a common language, religion, and culture. City-states called poleis governed independent territories and included democratic Athens and military Sparta. Athens and Sparta vied for power during the Classical period, fighting the Persian Wars and Peloponnesian Wars. Alexander the Great then conquered Greece and spread Greek culture across his vast empire before it was divided after his death, ushering in the Hellenistic period until Roman domination by the 1st century BC.