Alexander the Great (Greek: Αλέξανδρος ο Μέγας or Μέγας Aλέξανδρος,^[1][2] Megas Alexandros; July 20 356 BC – June 10 323 BC),^[3][4][5] also known as Alexander III, was an ancient Greek^[6][7][8] king (basileus) of Macedon (336–323 BC). He was one of the most successful military commanders in history, and was undefeated in battle. By the time of his death, he had conquered most of the world known to the ancient Greeks.

Following the unification of the multiple city-states of ancient Greece under the rule of his father, Philip II of Macedon (a labour Alexander had to repeat because the southern Greeks rebelled after Philip's death), Alexander conquered the Achaemenid Persian Empire, including Anatolia, Syria, Phoenicia, Judea, Gaza, Egypt, Bactria, and Mesopotamia, and extended the boundaries of his own empire as far as Punjab, India.

Prior to his death, Alexander had already made plans for military and mercantile expansions into the Arabian peninsula, after which he was to turn his armies to the west (Carthage, Rome, and the Iberian Peninsula). His original vision had been to the east, though, to the ends of the world and the Great Outer Sea, as described by his boyhood tutor Aristotle.

Alexander integrated many foreigners into his army, leading some scholars to credit him with a "policy of fusion." He also encouraged marriages between his soldiers and foreigners; he himself went on to marry two foreign princesses.

Alexander died after twelve years of constant military campaigning, possibly as a result of malaria, poisoning, typhoid fever, viral encephalitis or the consequences of alcoholism.^[9][10] His legacy and conquests lived on long after him, and ushered in centuries of Greek settlement and cultural influence over distant areas. This period is known as the Hellenistic Age, and featured a combination of Greek, Middle Eastern and Indian culture. Alexander himself was featured prominently in the history and myth of both Greek and non-Greek cultures. His exploits inspired a literary tradition in which he appeared as a legendary hero in the tradition of Achilles