Although it had won a hegemony over the Greek city-states from its leadership in the Persian Wars, the Spartan-led Peloponnesian League feared the growing power of the Athenian empire and worsened relations by repeated diplomatic affronts and demands. Wanting to deny any future Persian invasion a base from which to operate, Sparta had urged Athens, along with other Greek cities, to refrain from rebuilding their walls. However, suspecting a Spartan ploy and having already begun the work of construction, Athens employed subterfuge to delay the wheels of diplomacy until she could finish them.