Why Was the Monarchy Overthrown in Ancient Greece?
Monarchial rule – that is, rule by a king – was overthrown in ancient Greece because the monarchs' wealthy advisers and others in the aristocracy began to challenge the hereditary right of kings. The monarchy was eliminated in most ancient Greek city-states by 800 B.C. and replaced with an oligarchy -- rule by a privileged class of landowning aristocrats and wealthy merchants.
1 Tyranny
The oligarchy was in turn challenged in the sixth century B.C. by tyrants, military leaders who overthrew the aristocrats or monarchs in power, often with popular support. Many of the tyrants gained the support of the people by promising them more rights. In some cases, tyrants kept their promises and improved the lot of the citizens. In other cases, they ruled by fear as despots.
2 Democracy and Other Greek Government
The hoplites – Greek citizen-soldiers – rose to prominence under the tyrants. In some Greek city-states, such as Athens, the hoplites overthrew tyrants and enacted democratic forms of government. Athens practiced a form of direct democracy in which all free citizens were allowed to vote on community decisions in a general assembly. Other Greek city-states reverted to oligarchy, totalitarianism or – in the case of Sparta – a modified form of monarchy.