About BC 550, Cyrus I, emperor of Persia, conquered the territory of Ionia (the west coast of Modern Turkey). For all of their advances in science and mathematics, these well-established city-states seemed the most prominent in Greece. The people of Ionia, were discontent with their new, dictatorial rulers. The Persian rulers knew the feelings of the populace, but did little to alleviate the hostilities. Around BC 500, Artaphrenes, ruler of the western capital of Persia (Sardis) met with other leaders of Ionia. Seeing that many of them were anxious for gains in power and land, he made them agree not to attack each other. Artaphrenes knew that internal conflict could result in disintegration of the empire.
In BC 499, Aristagoras, the ruler of the Ionian city Miletus, yearned to control the city of Naxos. He tried to gain help from surrounding cities but failed. Fearing punishment from Darius I (Persian Emperor from BC 521-486) or Artaphrenes, for breaking the agreement, he incited a rebellion. Aristagoras encouraged the Ionians to remove their leaders. In response, many cities in the area rebelled and ousted their Persian rulers. Knowing that it would not be long until Darius retaliated, Aristagoras traveled to Sparta and appealed to King Cleomenes for aid. When the Spartan leader learned of the distance his army would travel to reinforce the Ionians, he declined the request for aid
Aristagoras, now desperate for support, went to Athens for help. The Athenians, fearing an inevitable attack by the Persians, decided to support Aristagoras and sent twenty