Alexander was the king of Macedonia who conquered an empire that stretched from Balkans to Pakistan. he was the son of Philip ll and Olympias(one of Philips seven or eight wives.
With an army of only around 40,000 men, he conquered the largest, richest and most powerful empire the world had ever seen; and all of this in less than a decade.
When Alexander became the king,his military career began when he launched a campaign against Macedonia northern neighbours. In 334, Alexander crossed Hellespont and invaded Asia.