Alexander was born in July 356 B.C. to Philip II and his third wife, Olympias. The parents were far from a happy couple, and Alexander was raised primarily under the influence of his mother. At the age of thirteen, he was sent to study with Aristotle–an education that was for the most part formal. Aristotle promoted the belief that non-Greeks were naturally slaves, thus encouraging the prince's thirst for conquest. Ultimately, however, Alexander would reject this belief, at least implicitly, as he attempted to cooperate with the Persians even as he subjugated them.

Returning to Macedonia after three years, Alexander soon had the opportunity to prove his strength in battle, as he subdued rebellions and contributed to his father's famous victory over Athens and Thebes at Chaeronea. But when Philip divorced Olympias and married Cleopatra, Alexander began to fear that his father was looking for a new heir, and the father and son had a falling out. Their dispute was shortly resolved, but both remained suspicious of the other. Indeed, Philip was soon assassinated by a guard who presumably had a personal grievance, though Alexander and his mother are traditionally thought to have played some kind of role in Philip's death.

Alexander thus succeeded to the throne and began the inevitable dynastic purging of enemies. At the same time, he had to force the other Greek city-states to acknowledge his authority as Hegemon of the Hellenic League, which Philip had established. In doing so, Alexander razed the city of Thebes as an example–though many sympathized with Thebes and only grew to resent Alexander more deeply. But Alexander had more important concerns–namely, the Persian expedition. This had been Philip's dream and Alexander's inheritance, and he wasted no time in beginning.

Alexander advanced gradually and conquered territory by territory until Darius, the Great King of Persia, was forced to come out himself to face Alexander. Alexander was victorious in the two key battles at Issus and Gaugamela, and Darius was murdered by conspirators soon afterward. In the meantime, Alexander also conquered Phoenicia, Egypt, and Babylon, all of which proved to be valuable acquisitions.

Upon hearing of Darius's death, the Macedonian army assumed that the expedition was over and the war won, but Alexander insisted on pushing farther east. Here he faced a formidable opponent in Spitamenes, who possessed a smaller army but continued harassing Alexander and even slaughtered a Macedonian unit after Alexander underestimated him. Spitamenes was ultimately defeated, the rebellion fell apart, and Alexander went on to conquer the Paraetacene territory. In the Far East, Alexander founded a large number of cities that would contribute to the expansion of Greek culture.

Finally there remained India (which at the time referred to a small area in western Pakistan, not the country of modern times). Although Alexander was already the undisputed king of Asia, he would not be satisfied until he had personally vanquished the entire continent. He soon allied himself with one ruler, Ambhi, but there remained Ambhi's enemy Porus. The result was one of Alexander's greatest military achievements, but the battle was difficult, particularly because the Macedonian army had had to face a frightful experience in fighting elephants.

After India, Alexander wanted to press still farther, recognizing that Asia extended beyond what he may have expected from limited geographical knowledge. At this point, however, his troops finally refused to further, and mutinous thoughts stirred after eight hard years of combat and marching. Alexander was furious, but he was eventually forced to give in and return home.

Back in Persia Alexander dealt with administrative matters, including the replacement of various satraps, or local rulers. More important, his experience of Asia had changed his attitude toward Persians. His desire to cooperate with the Persians alienated many conservative Macedonians, who still viewed Persians as barbarians. Alexander's new attitude may even have led to his death in 323 B.C. Though the official cause of his death was a fever aggravated by heavy drinking, many historians have speculated that Alexander was poisoned by Aristotle, his former tutor, and Antipater, his close advisor, as a result of his favorable treatment of the barbarians.