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 Diogenes 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."