Features of the Greek polis from the Dark Ages

Describe the basic features of the Greek polis from the Dark Ages to the Macedonian Conquest. Which factors contributed to the unity of the Greek-speaking peoples, and how was this unity manifested in Greco-Persian Wars? Conversely, which factors tended to provoke conflict among poleis, and how did these tensions erupt into the Peloponnesian Wars? Why were the Greeks so poorly prepared to meet the threat posed to their independence by Phillip of Macedon?