Alexander, at the time of his father's death, was in his twentieth year, having been born in B.C. 356. His early education was entrusted to Leonidas, a kinsman of his mother, a man of severe and parsimonious character, who trained him with Spartan simplicity and hardihood; whilst Lysimachus, a sort of under-governor, early inspired the young prince with ambitious notions, by teaching him to love and emulate the heroes of the Iliad. according to the traditions of his family, the blood of Achilles actually ran in the veins of Alexander; [His mother Olympias was the daughter of Neoptolemus, king of Epirus who claimed descent from Pyrrhus, the son of Achilles.] and Lysimachus nourished the feeling which that circumstance was calculated to awaken by giving him the name of that hero, whilst he called Philip Peleus, and himself Phoenix. But the most striking feature in Alexander's education was, that he had Aristotle for his teacher, and that thus the greatest conqueror of the material world received the instructions of him who has exercised the most extensive empire over the human intellect. It was probably at about the age of thirteen that he first received the lessons of Aristotle, and they can hardly have continued more than three years, for Alexander soon left the schools for the employments of active life. At the age of sixteen we find him regent of Macedonia during Philip's absence; and at eighteen we have seen him filling a prominent military post at the battle of Chaeronea.

On succeeding to the throne Alexander announced his intention of prosecuting his father's expedition into Asia; but it was first necessary for him to settle the affairs of Greece, where the news of Philip's assassination, and the accession of so young a prince, had excited in several states a hope of shaking off the Macedonian yoke. Athens was the centre of these movements. Demosthenes, although in mourning for the recent loss of an only daughter, now came abroad dressed in white, and crowned with a chaplet, in which attire he was seen sacrificing at one of the public altars. He also moved a decree that Philip's death should be celebrated by a public thanksgiving, and that religious honours should be paid to the memory of Pausanias. At the same time he made vigorous preparations for action. He despatched envoys to the principal Grecian states for the purpose of inciting them against Macedon. Sparta, and the whole Peloponnesus, with the exception of Megalopolis and Messenia, seemed inclined to shake off their compulsory alliance. Even the Thebans rose against the dominant oligarchy, although the Cadmea was in the hands of the Macedonians.

The activity of Alexander disconcerted all these movements. Having marched through Thessaly, he assembled the Amphictyonic council at Thermopylae, who conferred upon him the command with which they had invested his father during the Sacred War. He then advanced rapidly upon Thebes, and thus prevented the meditated revolution, The Athenians sent ambassadors to deprecate his wrath, who were graciously accepted. He then convened a general congress at Corinth, where he was appointed generalissimo for the Persian war in place of his father. Most of the philosophers and persons of note near Corinth came to congratulate him on this occasion; but Diognes of Sinope who was then living in one of the suburbs of Corinth, did not make his appearance. Alexander therefore resolved to pay a visit to the eccentric cynic, whom he found basking in the sun. On the approach of Alexander with a numerous retinue, Diogenes raised himself up a little, and the monarch affably inquired how he could serve him? "By standing out of my sunshine," replied the churlish philosopher. Alexander was stung with surprise at a behaviour to which he was so little accustomed; but whilst his courtiers were ridiculing the manners of the cynic, he turned to them and said, "Were I not Alexander, I should like to be Diogenes."

The result of the Congress might be considered a settlement of the affairs of Greece. Alexander then returned to Macedonia in the hope of being able to begin his Persian expedition in the spring of B.C. 335; but reports of disturbances among the Thracians and Triballians diverted his attention to that quarter. He therefore crossed Mount Haemus (the Balkan) and marched into the territory of the Triballians, defeated their forces, and pursued them to the Danube, which he crossed. After acquiring a large booty he regained the banks of the Danube, and thence marched against the Illyrians and Taulantians, whom he speedily reduced to obedience.