Political Structure

Ancient Greece consisted of several hundred more or less independent city-states (poleis). This was a situation unlike that in most other contemporary societies, which were either tribal, or kingdoms ruling over relatively large territories. Undoubtedly the geography of Greece—divided and sub-divided by hills, mountains and rivers

Contributed to the fragmentary nature of ancient Greece. On the one hand, the ancient Greeks had no doubt that they were 'one people'; they had the same religion, same basic culture, and same language. Furthermore, the Greeks were very aware of their tribal origins; Herodotus was able to extensively categorise the city-states by tribe. Yet, although these higher-level relationships existed, they seem to have rarely had a major role in Greek politics. The independence of the poleis was fiercely defended; unification was something rarely contemplated by the ancient Greeks. Even when, during the second Persian invasion of Greece, a group of city-states allied themselves to defend Greece, the vast majority of poleis remained neutral, and after the Persian defeat, the allies quickly returned to infighting.

Initially many Greek city-states seem to have been petty kingdoms; there was often a city official carrying some residual, ceremonial functions of the king (basileus), e.g. the archon basileus in Athens.However, by the Archaic period and the first historical consciousness, most had already become aristocratic oligarchies. It is unclear exactly how this change occurred. For instance, in Athens, the kingship had been reduced to a hereditary, life-long chief magistracy (archon) by c. 1050 BC; by 753 BC this had become a decennial, elected archonship; and finally by 683 BC an annually elected archonship. Through each stage more power would have been transferred to the aristocracy as a whole, and away from a single individual.
Inevitably, the domination of politics and concomitant aggregation of wealth by small groups of families was apt to cause social unrest in many poleis. In many cities a tyrant (not in the modern sense of repressive autocracies), would at some point seize control and govern according to their own will; often a populist agenda would help sustain them in power. In a system racked with class conflict, government by a 'strongman' was often the best solution.
Athens fell under a tyranny in the second half of the 6th century. When this tyranny was ended, the Athenians founded the world's first democracy as a radical solution to prevent the aristocracy regaining power. A citizens' assembly (the Ecclesia), for the discussion of city policy, had existed since the reforms of Draco in 621 BC; all citizens were permitted to attend after the reforms of Solon (early 6th century), but the poorest citizens could not address the assembly or run for office. With the establishment of the democracy, the assembly became the de jure mechanism of government; all citizens had equal privileges in the assembly. However, non-citizens, such as metics (foreigners living in Athens) or slaves, had no political rights at all.
After the rise of the democracy in Athens, other city-states founded democracies. However, many retained more traditional forms of government. As so often in other matters, Sparta was a notable exception to the rest of Greece, ruled through the whole period by not one, but two hereditary monarchs. This was a form of diarchy. The Kings of Sparta belonged to the Agiads and the Eurypontids, descendants respectively of Eurysthenes and Procles. Both dynasty founders were believed to be twin sons of Aristodemus, a Heraclid ruler. However, the powers of these kings was trammeled by both a council of elders (the Gerousia) and magistrates specifically appointed to watch over the kings

Thus, the major peculiarities of the ancient Greek political system were; firstly, its fragmentary nature, and that this does not particularly seem to have tribal origin; and secondly the particular focus on urban centres within otherwise tiny states. The peculiarities of the Greek system are further evidenced by the colonies that they set up throughout the Mediterranean Sea, which, though they might count a certain Greek polis as their 'mother' (and remain sympathetic to her), were completely independent of the founding city.

Inevitably smaller poleis might be dominated by larger neighbours, but conquest or direct rule by another city-state appears to have been quite rare. Instead the poleis grouped themselves into leagues, membership of which was in a constant state of flux. Later in the Classical period, the leagues would become fewer and larger, be dominated by one city (particularly Athens, Sparta and Thebes); and often poleis would be compelled to join under threat of war (or as part of a peace treaty). Even after Philip II of Macedon 'conquered' the heartlands of ancient Greece, he did not attempt to annex the territory, or unify it into a new province, but simply compelled most of the poleis to join his own Corinthian League.