In the 5th Century BC, the classical Greek city-states were at their apex of power and glory, with Athens and Sparta as the two strongest powers. Greece was not a united nation at this time, even during the wars against the two Persian invasions of Darius and Xerxes, which had ended in total defeat of the would-be conquerors at the naval battle of Salamis and the land battles of Marathon and Plataea. After this time, the Athenian and Spartan empires clashed over which state would be hegemonic, and essentially fought each other to exhaustion and bankruptcy over thirty years during the Peloponnesian War. This provided the opportunity for Philip II of Macedonia to sweep down from the north and impose his own system of rule, no matter that most Greeks regarded him as a barbarian.
Athens and its Delian League had a far stronger and more extensive overseas empire than Sparta, and a more developed system of trade and commerce. During the classical age, it also produced the great philosophers Socrates, Plato and Aristotle, whose ideas were extremely important to Western civilization for the next 2,000 years. So were the playwrights Aeschylus, Sophocles, and Euripides, the founders of the Western dramatic tradition, and the early historians Herodotus and Thucydides, who wrote about the Persian and Peloponnesian Wars. Most of the time, Athens also maintained a democratic government that was highly unusual in the ancient world, although only adult males with property (perhaps 60,000 out of the total population of 350,000) were considered actual citizens eligible to vote and hold office. Every year, all public officers were elected by the popular assembly or ekklesia, although in practice small farmers and artisans could not attend its meetings regularly, unlike the wealthier aristocrats, oligarchs and professional demagogues. Trade, commerce and manufacturing were generally in the hands of foreigners or metics, who were generally not eligible to become citizens, but like all societies in the ancient world most of the population worked in agriculture. Pericles was one of the demagogue politicians, trained by the Sophists as Socrates and Plato called them, whose rule was not a golden age but ultimately a catastrophe, since he provoked the war with Sparta in 431 BC. After nearly thirty years of war, plague and famine, the Spartans finally destroyed Athens and imposed their own rule over Greece and its overseas colonies. Civil war continued for decades afterwards as a coalition led by Thebes overthrew Spartan rule in 371 BC, and then Athens and its allies fought against the Thebans until Philip II of Macedonia imposed his own rule.
Under the leadership of Alexander the Great, the armies of Macedonia conquered the Persian Empire and reached the borders of India, although this Hellenistic empire fragmented after his death. Alexander’s father, King Philip II, had already completed the conquest of Greece in 338 BC and abolished the system of independent city-states, which would never exist again. Philip was assassinated before he could launch the invasion of Persia, possibly with the complicity of Alexander and his mother Olympias, who ruled as regent in Greece after he began his wars of conquest. Within three years, he had destroyed the Persian state and taken his armies through Afghanistan and to the Indus River, but his troops mutinied and forced him to return to Persia. He was in Babylon, planning the invasion of Arabia, when he died in 323 BC, either from disease or being poisoned by his own generals. Alexander established a number of Greek cities in the east named after himself, the most important of which was Alexandria, Egypt, a center of commerce and learning under the Ptolemaic and later Roman rulers. These were not independent city-states but all ruled by kings, up until the time that the Romans conquered the Hellenistic East. Women in Egypt and other Hellenistic states were able to vote and hold office, and the most famous of the Macedonian queens of Egypt was Cleopatra. Alexandria also had the largest library in the ancient world, at least up to the time of its destruction by Julius Caesar during the Roman conquest.
Throughout the Hellenistic era and on through the Roman and Byzantine periods, the dominant art, language, culture and philosophy of the East was Greek. Among its leading cultural figures were the playwright Menander of Athens, creator of dramatic comedies, Diogenes the Cynic philosopher, Zeno, the founder of the highly influential school of Stoic philosophy, and Epicurus. Stoicism and its emphasis on order and duty was the most important in the Roman world, rather than the pleasure-seeking philosophy of the Epicureans. Other great accomplishments of Hellenistic civilization included the geometry of Euclid, the astronomy of Ptolemy and Hipparchus, and the medical advances of Galen and Herophilus of Chalcedon. Not all the natives of the East accept the hegemony of the Greek rulers, and there were major rebellions of traditionalist Jews (the Maccabees) against their Seleucid overlords in 167 BC, just as there were later revolts against the Romans. Nor did the Persians remain long under Greek control, although it had been the wish of Alexander to unite the two peoples.
Kishlansky, Mark, Patrick Geary, and Patricia O'Brien. Civilization in the West, Volume One, 7th Edition. Pearson, 2008.