Throughout the course of ancient Greek history, many tyrants rose and fell. Employing both practical and devious means to take over, they sometimes succeeded in various city-states to establish stable regimes. Other cities and towns, too small to attract the gaze of potential conquerors, existed under the rule of established elites or as democracies. However, no single tyrant or governing body in ancient Greece was able to unite all of the city-states into one united nation.

The Greek Polis

The Greek polis, or city-state, was small, sometimes even tiny, and existed under various types of rule. Among the more than 1,500 city-states that developed in ancient Greece, Athens was unusual with its large population of over 200,000. Other prominent poleis included Corinth, with 10,000 people, and Sparta, which had even fewer -- most of whom were slaves. But whether a monarchy, oligarchy or democracy, they all had one thing in common. The citizens of each polis -- the wealthy or land-owning males -- were expected to take an active role in society and in politics. Even Sparta, which was ruled by a military elite, had an assembly that helped guide its highest councils.

The Geography

Though city-states, villages and hamlets sprang up all over Greece, geography prevented them from uniting under one rule of law. Water was a dividing factor, as civilization in the region developed on many different islands, rather than on one continent. On the islands, mountains hindered travel, trade and communication between populated areas. Consequently, local governments arose, each with its own leaders, character and method of rule. For example, though Athens and Thebes were only about 60 miles apart, they evolved so differently -- Athens into a democracy and Thebes into an oligarchy -- that they developed a bitter rivalry highlighted by the Theban alliance with Persia against Greece during the Persian Wars.

The Mediterranean Sea

Early Greeks had a pioneering spirit that often led them away from their own city-states to colonize on other islands or even along the coasts of other countries such as Italy, Turkey and France. The dearth of arable land on the Greek islands coupled with the invitingly calm waters of the Mediterranean Sea enticed many Greeks to become sailors. Setting out when overcrowding or crisis threatened their prosperity, they steered a course to a new life somewhere more hospitable. The founders of these new colonies felt no obligation to remain under the rule of their former land, creating an even bigger challenge to Greek unification.

Aristocratic Power

The various aristocracies of the Greek city-states further prevented unification of the country under one government. The word aristocracy itself is Greek, meaning "rule of the best." This right to rule came to the Greek nobility not from mere birth, but also from wealth and social standing. Their power derived from how connected they were to others of influence in the political arena. Such aristocrats were unlikely to view the imposition of a ruling tyrant or monarch as welcome or wise. Even would-be usurpers recognized the power of the entrenched aristocracies, seeking ways to conquer from within. In 632 B.C., the tyrant Theagenes of Megara married his daughter to Cylon, a member of the noble class of Athens. Together, they conspired to take over that city-state. However, Cylon failed and was executed. Many others met the same fate over the course of Greek history.