Alexander III of Macedon, commonly known as Alexander the Great, was a king of the ancient Greek kingdom of Macedon and a member of the Argead dynasty. He was born in Pella in 356 B.C. and succeeded his father Philip II to the throne at the age of twenty. He spent most of his ruling years on an unprecedented military campaign through Asia and northeast Africa, and he created one of the largest empires of the ancient world by the age of thirty, stretching from Greece to northwestern India. He was undefeated in battle and is widely considered one of history's most successful military commanders.
Alexander became legendary as a classical hero in the mold of Achilles, and he features prominently in the history and mythic traditions of both Greek and non-Greek cultures. He became the measure against which military leaders compared themselves, and military academies throughout the world still teach his tactics.
Alexander married three times: Roxana, out of love; and Stateira II and Parysatis II for political reasons. In addition, he had a long and close (and generally assumed romantic) relationship with his friend, general, and bodyguard Hephaestion, the son of a Macedonian noble. Hephaestion's death devastated Alexander. This event may have contributed to Alexander's failing health and detached mental state during his final months.