"In the first years following Alexander’s death, Ptolemy (like the other so-called Successors) continued to mint the traditional coinage that had been issued by his hero. The main type of coin had shown Alexander’s putative ancestor Herakles (Hercules) wearing on his head the lion scalp that commemorated one of his legendary labors. It was, after all, normal Greek practice to reserve the “heads” side of a coin for the portrait of just such a god or goddess: Athena at Athens, Persephone at Syracuse, Helios at Rhodes and so forth. Then Ptolemy dared take a step that has stirred no end of debate among scholars—one that, in essence, threw a rock into the still waters of Greek art and religion, sending great ripples outward through time and place to Sicily, Syria, Rome and beyond: Ptolemy replaced the portrait of Herakles on Alexander’s posthumous coinage with a stunning image of another god—Alexander himself."
See the above page (the second link) for the full story.