 Complete the following phrase:  The regions comprising modern Syria and Pakistan have been under the rule of contiguous empires at various points in history, including during the reign of the Persian Empire, the conquests of Alexander the Great, Seleucid Empire and Sassanid Persia. However, the most influential impact was made during the duration of the Umayyad Caliphate, which stretched from Spain to India at its height and was centered at Damascus. The 