How did Alexander the great help to spread Greek culture?

Alexander waged perhaps the most astonishing military campaign in history. From his ascension to the throne of Macedon in 336 BC to his death in 323, Alexander conquered most of the known world. As he conquered Asia, he brought the Greek language and culture with him; this process was known as "Hellenization." He also founded as many as 70 cities, each of which was settled by Greek-speaking colonists. Moreover, Alexander instituted a single system of coinage in his empire; this helped to unify the eastern and western portions of his kingdom.

Alexander's empire fell apart shortly after his death, but the influence of Greek culture remained. Thus, when the Romans eventually wrangled control of its ruins, they retained Greek as an international language of diplomacy (much as French was throughout most of modern European history and English is today). In these ways, Alexander helped spread Greek culture across the world.