<Tr> <Th> Mother </Th> <Td> Olympias of Epirus </Td> </Tr> <Tr> <Th> Religion </Th> <Td> Greek polytheism </Td> </Tr> <P> Alexander III of Macedon (20 / 21 July 356 BC--10 / 11 June 323 BC), commonly known as Alexander the Great (Ancient Greek: Ἀλέξανδρος ὁ Μέγας, translit . Aléxandros ho Mégas, Koine Greek: (a. lék. san. dros ho mé. gas)), was a king (basileus) of the ancient Greek kingdom of Macedon and a member of the Argead dynasty . He was born in Pella in 356 BC 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 . </P> <P> During his youth, Alexander was tutored by Aristotle until age 16 . After Philip's assassination in 336 BC, he succeeded his father to the throne and inherited a strong kingdom and an experienced army . Alexander was awarded the generalship of Greece and used this authority to launch his father's pan-Hellenic project to lead the Greeks in the conquest of Persia . In 334 BC, he invaded the Achaemenid Empire (Persian Empire) and began a series of campaigns that lasted ten years . Following the conquest of Anatolia, Alexander broke the power of Persia in a series of decisive battles, most notably the battles of Issus and Gaugamela . He subsequently overthrew Persian King Darius III and conquered the Achaemenid Empire in its entirety . At that point, his empire stretched from the Adriatic Sea to the Indus River . </P>

Who was crowned king of macedonia when he was 20