The epic story of the imperial rivalry between two of the greatest empires of the ancient world - Parthian and Persian - and how they rose and eventually fell. The Roman empire shaped the culture of the western world against which all other great powers are compared. Stretching from the north of Britain to the Sahara, and from the Atlantic coast to the Euphrates, it imposed peace and prosperity on an unprecedented scale. However, the exception lay in the east, where the Parthian and then Persian empires ruled over great cities and the trade routes to mysterious lands beyond. This was the place Alexander the Great