Map of Persia; Ancient and Modern. Understanding that the boundaries always greatly fluctuated; the largest extent of the Persian Empire was under (1) the Achaemenians (539-330 BC); (2) the Parthians (165 BC-AD 226); (3) the Sasanians (AD 226-651); the Mongols (AD 1256-1344). From the time of Khusru Parvez (Sasanian); AD 562; till the end of the Caliphate; 1258; Yemen (Arabia) was nominally under the suzerainty of Persia. Illustration for Hutchinson's History of the Nations (Hutchinson; c.1920).