The Greeks originated from migrations of people from the areas around Mesopotamia to Greece around 2000 BC. Two early civilizations, the Minoans and Mycenaeans, influenced later Greek culture before going into decline. The Greeks developed many independent city-states, with Sparta focusing on militarism and Athens nurturing democracy, philosophy, and the arts. Athens repelled the Persian invasions in the 5th century BC, beginning a period of cultural achievement, but was later weakened by war with Sparta. Alexander the Great then spread Greek culture throughout his vast empire before his early death.