Alexander the Great, born in 356 BCE in Macedonia, was a king and one of history's most successful military commanders. Tutored by Aristotle, he ascended to the throne at age 20 after his father, King Philip II, was assassinated. Over the next decade, Alexander built a vast empire, stretching from Greece to Egypt and into northwest India. Known for his tactical genius and ambitious vision, he spread Greek culture and influence throughout the known world, a period known as the Hellenistic Age.