The images of Alexander the Great that we have show a remarkable unity of style. Coins produced in Egypt and statues from Persia depict him with the same key traits, despite different local artistic traditions. He is always portrayed looking slightly upward, with a wistful expression and flowing hair.
Contemporary descriptions of him indicate that this is close to reality. He had an anastole at the top of his forehead, from which his hair cascaded back, and the facial expression seems to have been characteristic.
After his death, his generals divided his conquests into individual kingdoms, and the depictions of the successor kings reverted to local artistic styles. However, every now and then a successor king would try to recreate Alexander's conquests. At that point, the local coinage tended to undergo a change: the king's head would sprout flowing locks and that upward, wistful look.
Even the Romans were not immune to the power of his iconography. One of Caesar's rivals, Pompey, styled himself after Alexander. He took the cognomen "Magnus", meaning "The Great". He also had a cowlick at the top of his forehead, and his supporters claimed he had a resemblance to Alexander - "something about the eyes". (His enemies described this resemblance as "more discussed than visible.") Pompey's bust shows him with short but flowing hair and a slight upward look. This is in contrast to the images of his contemporaries, such as Caesar, whose lean cheeks and close-cropped hair were more the Roman norm. Not that it helped Pompey, whose attempt at world rule ended in defeat by Caesar
The appeal of Alexander the Great can still be seen in modern times. John F. Kennedy, now an icon in is own right, was often photographed with an upward, wistful expression and a certain freedom about the hair.