The reforms of Kleisthenes (507 BC) established the first democratic process in the social system of Athens, instituting the demos (body of citizens) as an autonomous political entity. The glorious victories of the Greeks in the Persian Wars (490-479 BC), during which Athens played a leading role, marked the transition from the Archaic to the Classical period and inaugurated a Golden Age for the city of the goddess of wisdom. Athens had become an economic and cultural center with a consolidated democratic regime. Shielding all Ionian Greeks against the Persian threat through their union in the First Athenian League for (478/7 BC), headquartered initially in Delos and after 454 BC in Athens, would give the Athenian city-state the dimensions of a hegemony. The reforms of Ephialtes in (462/1 BC) and even more so those of Pericles (451/0 BC), with the supremacy of the demos, the election of the archons by lot and their obligation to be answerable for their actions, made the citizen of participants in the decision-making process and the management of the affairs of his city. The undoubted pinnacle of the Classical art of the 5th century was the architecture and sculptural decoration of the Parthenon (447-432 BC), where the divine is interwoven with the human element and man is designated as the constant and inviolable measure of the values of this civilization. In sculpture, the body now moves freely in space, shifting its center of gravity, while vase painters, taking advantage of the possibilities offered by the red - figure style, an Athenian invention of the years around 530 BC, focus on the study of the human form. Parading alongside the mythical figures are ordinary people in scenes from everyday life, which should be interpreted as representations of an imaginary world. The eternal concerns of human existence formed the subject of the tragic poetry of Aeschylus, Sophocles and Euripides, the sharp criticism of Aristophanes' comedies, the philosophical meditation of the Sophists, of Democritus, Anaxagoras and Socrates. Realization of the link between past, present and future gave birth to historical consciousness in the works of Herodotus and Thucydides, who recorded the events of the Peloponnesian War (431-404 BC) as the dramatic culmination of the expansionist tendencies of Athenian policy. The defeat of democratic Athens by the Spartan oligarchy and the turmoil of war affected not only Athenian society but, inevitably, art as well. The world of harmony came crashing down as passion gained ascendancy over morality, while the strong decorative tendency in the art of the time was most likely kindled by recollections of the glorious past. By the 4th century BC Athens and Sparta had lost their leading position, the Persian Empire -which had contributed to Sparta's victory in the Peloponnesian -War secured its political influence in Greek affairs, and the rest of the Greek city-states became embroiled in local power struggles. The destabilization of political life facilitated the dominance of the Macedonians under Philip II who, after the Battle of Chaeronea and the conquest of the cities of southern Greece (338 BC), assured peace. Athens experienced an economic downturn in this transitional period, the immediate result being a drop in exports of its once highly sought-after vases. The study of human passions was reflected in the supple bodies portrayed in sculpture with their freedom of movement their grace and sensuality. In the domain of philosophical meditation, these conditions led to a transcendental interpretation of the basic concepts of life, as formulated in Plato's theory of Ideas, which in conjunction with empirical observation would lay the foundations for scientific research in the work of Aristotle. The influence of these two philosophers would remain strong even into modern times.