When these wars broke out, the Persian Empire was the largest empire the world had ever seen. They had expanded across Asia, Asia Minor, and parts of North Africa. The ruler of the Persian Empire was King Darius and he saw Greece as a perfect place to expand his empire. He invaded a Greek colony called Ionia. Darius demanded tribute, and the Ionians were furious, so they asked the city-state of Athens to help them, Athens then sailed to Ionia and defeated the Persians, and they turned back, shortly after, the Persians returned and crushed the Ionians and destroyed the city of Miletus. This sparked the Persian-Greek Wars when the Persians marched into Greece. The Battle of Marathon The Battle of Marathon was between the Athenians aided by the Plataeans against a Persian army commanded by Datis and Artaphernes. The Persians sailed to a port near the city-state of Marathon, from there they sent the Persians marching into the plains of Marathon, where the Athenians and Plataeans were blocking the exits of the plains. Knowing that the small Greek army had no chance of facing him ...