Whereas many ancient nations developed into large states, the peoples of Greece formed a much more unique kind of political organization, that of the polis. The polis were city-states, of which there were many in Ancient Greece, some of the most notable including Athens, Sparta, and Corinth. At the early stages, each polis was ruled over by a monarch, though this was changed throughout history.
Some of the weaknesses of the polis as a political structure can be immediately recognized. For example, the small size of a city-state compared to that of a large nation-state leads to a variety of potential problems. An individual polis could be easily invaded by the army of a nation-state, however as the polis often had alliances with one another, this was not usually the case. As a result of their small size, the polis tended to be war oriented, particularly among their neighbors in Greece. This in part led to another weakness; the ease in which the ruling government over a polis could be overthrown, a scenario which occurred frequently among the city-states. Often when the citizens became dissatisfied with their ruler, one would rise who would take power. Unfortunately, the new ruler often proved to be a tyrant.
However, the polis also had a number of strengths, which is no doubt why their existence continued over several centuries. One strength was based on what has already been designated as a potential weakness—the small size. Small city-states allowed for ample experimentation in the political realm, which is why the polis were ruled over by a variety of governments, including monarchies, tyrannies, oligarchies, and limited democracies. It was through this experimentation that the Greeks developed the idea of a republic, which we have inherited in today’s world. As well, the polis spawned the concept of naturalization, in which foreigners could become Greek citizens, which eventually led to the Greek idea of a common universal culture. As well, the polis shared a common language and similar culture which those surrounding city-states, which led Greece to become a strong cultural and political force.
Although the polis did have the weaknesses mentioned, it would seem that they were overshadowed with the strengths. For this reason, the polis continued to be the dominant form of Greek government for centuries, and contributed many ideas about government that have been passed on to us in the present.