After the Persian wars, Athens became the supreme naval power in Grece. It created the Delian League to ward off possible Persian attacks. Athenas grew so powerful that they could dictate the laws, customs, and trade of all her neighbors in Attica and the islands of the Aegean. This power made the Athenian policy makers arrogant and intolerant with other city-states. Thus creating a discontent of the Greek polis.