Political questions are raised by many of the pre‐Classical Greek poets and thinkers, from Homer's thoughts on kingship (probably mid‐ to late eighth century bc), to the Athenian lawgiver and poet Solon c.600 bc. Nevertheless it is not until the mid‐fifth century bc that sophists such as Protagoras and Antiphon introduced systematic political theory, supported by rational argument; their central concern was the relation between ‘nature’ and ‘convention’ and the question of whether obedience to the state's laws and conventions was to the individual's advantage. A keen interest in these and other political questions can also be found around this time in the works of the Athenian tragedians, and the historians Herodotus and Thucydides. Methods of political analysis were greatly developed by Socrates, and Greek political thinking in general reaches its culmination in the fourth century bc with the radical idealism of Plato and the more conservative and pragmatic work of Aristotle.
A number of historical reasons help explain why this relatively brief flourishing of systematic and practical political thought in Greece occurred when it did. By the mid‐fifth century bc the independent city‐state or polis (from which our word ‘politics’ derives) was well established as the basic unit of political organization in Greece, and the many different forms that the polis took—from the oligarchical and military regime of Sparta to the radical participatory democracy of Athens—prompted comparisons and the question of which form was best. Increasing travel and the nascent disciplines of history and anthropology provided further data for comparison, and the continuing practice of colonization around the Mediterranean gave real urgency to the question of how the polis should be structured, and provided a field for political experiment and theorizing. Nor is it a matter of chance that such theorizing tended to originate in Athens: her participatory democracy (albeit limited to adult freeborn males) both encouraged political debate and offered the practical experience to inform such debate. Furthermore, though democracy was generally in the ascendant at Athens, oligarchical factions remained powerful and the tensions between the two parties required each to produce political theories in its support. Young men of either party who desired political influence required training in rhetoric and argument, and the sophists arose partly to supply such needs.
Thus when Philip of Macedon and his son Alexander the Great destroyed the autonomy of the polis in the last forty years of the fourth century bc, serious practical contributions to Greek political thought largely ceased. After this, philosophy tended to concentrate on the individual in isolation (as for instance in the philosophy of Epicurus), rather than on relations between the individual and the state. The intriguing Stoic notion of the ‘cosmopolis’ (perhaps influenced by Alexander's own ambitions to create a world‐state) was not intended as a practical manifesto for reform. It is rather a utopian vision in which all separate states and political and economic institutions have crumbled, and individuals are united by the ties of friendship and common humanity alone.
Historical circumstances also account for many of the issues prevalent in Greek political theory: the range of data available gives rise to a tendency to rank constitutions and a corresponding tendency to create fictional ideal states (as opposed to the Stoic world community) to serve as the blueprints for such rankings: Plato's Republic and Laws and the last two books of Aristotle's Politics are notable examples. The very different criteria for citizenship employed by the different states also prompted the question of what citizenship really meant and who was eligible for it. As a result of the constant tensions between oligarchic and democratic factions the issue of stability was crucial for Plato and Aristotle; in contrast, the accent in Athenian democracy on individual participation raised the sense of the individual's importance, and highlighted the question of relations between individual and state.