Peloponnesian Wars: From 431 to 404 BC Peloponnesian war took place. Athens, leading the Delian League, tried to get the control over all the polis. But it was defeated, and poblems continued. After the battle of Hellespont (405 BC), Sparta took control over Athens. This decadence was exploited by other cities, such as Thebes, which fighting in a phalanx, defeated Sparta and for some time it became the leading city in Greece. But while the Greek cities were fighting each other, a new power was arising up in the North, Macedonia.