The battle of Marathon was a decisive Athenian victory over the Persian Empire in 490 BCE. The battle effectively ended the Persian invasion of Greece and prevented the Persians from gaining control of the Aegean Sea. The victory at Marathon boosted the morale of the Athenians and gave them confidence in their own abilities. As a result, the Athenians began to expand their power in the region and eventually became the dominant naval power in the Mediterranean Sea.