Sparta In Ancient Greece

As victors, the Spartans found themselves dominant in a Greece where polis was suspicious of polis and where, within each polis, faction disputed with faction. From Ionia, which the Spartans sold back to Persia as the price of their assistance, the Persians loomed once more as a threat to the whole Greek world. The new Macedonia in the north menaced the Greeks. Perhaps wiser or more vigorous leaders would have been able to create some sort of federation among the individual poleis that could have withstood the Persians and the Macedonians, and still later, the Romans. But since this did not happen, it seems more likely that the polis as an institution was no longer thought to be the appropriate way for the Greek world to be organized. Perhaps it was too small, too provincial, and too old-fashioned to keep the peace and provide scope for economic advancement and intellectual growth.
The Spartans could not pose as the leaders of Greece and keep their bargain with the Persians to sell Ionia back to them. And if they went back on the bargain, the Persians would start a new war. When Cyrus the governor of the Asian Minor, the younger brother of Artaxerxes II and king of Persia, rebelled against him he asked Sparta for aid and Sparta gave it to him. Cyrus was soon killed in a battle in Mesopotamia, and his Greek army was stranded in Persia. This then left the Spartans at war with