The Hellenistic Period (336 to 30 BC) - Alexander The Great's military genius
Already by 346 B.C. the wise opponent of Demosthenes, the orator Isocrates, who was also an Athenian, conjured the participating Macedonian King Philip, during the Pythic Games, to try to enforce peace between the dissenting Greek cities (*). Isocrates' invitation added to the invitation by the Amphictyonic League led the Macedonian King to his final decision. In Athens, however, the parochial views of Demosthenes prevailed. Thus the battle of Cheronea (338 B.C.) was fought, and the Macedonian King defeated the Athenians and the Thebans. The victorious Philip behaved towards the Athenians with great magnanimity. He honored the prisoners and the wounded. He did no harm to the town. On the contrary, he was ruthless towards the Thebans.After such a victory the leadership of the Macedonians over all Greeks was generally accepted, with the exception of the Spartans. The Macedonian King called a general assembly of all Greeks, the Panhellenion at Corinth, where the war against the Persians was resolved. But Philip II was murdered and his son Alexander III, known as the Great (356-323 BC) succeeded to the throne.
This King was fortunate enough to bring to a successful end his father's plan, and to conquer Asia as far as the Indus river, and much beyond the Caspian Sea. One marvels at this Macedonian King's military genius!
Reorganizing his army, he started from Greece and Macedonia and with the primitive technical means of that time, collecting information of strategic and tactical interest, he fought a first pitched battle with the Persians on the river Granicos in Asia Minor, not far from the sea of Marmara (334 B.C.). The Macedonian cavalry gave the victory to the Macedonian King whose troops were qualitatively superior but numerically inferior to the Persian army. After his victory the Macedonian King sent three hundred enemy panoplies (full armor), to the Parthenos Athena at the Parthenon Temple in Athens, with a dedication proving beyond doubt that Alexander the Great considered the Macedonians, his fellow countrymen, as Greeks.
A second important battle followed in November 333 B.C. at Issos (in Cilicia, Asia Minor, near the gulf of Alexandretta). In this battle, the Persian King was in personal command of his army. In spite of the great numerical superiority of the Persians, victory once more crowned the arms of the Macedonian King, thanks to the great personal contribution of Alexander the Great, to superiority of equipment due wholly to the Greek King, and to the tactical formations and finally to the higher morale of the Greeks. After the victory at Issos, Alexander marched to Egypt; he founded the city of Alexandria, where he constructed harbor works of amazing proportions; he won over to his side the Egyptian priesthood; he destroyed the Persian naval bases on the Meditarranean coasts, and then turned to pursue the Persians to the innermost parts of Asia. In October 331 B.C. he gave the third battle against the Persians at Gaugamela, where they were completely annihilated.
(*) "Greece" A short History. By M. A. Hamilton, Oxford