East of the Zagros Mountains lay Media and Persia proper,--Media,
northeastward, towards the Caspian Sea; and Persia, on the tableland of
Iran stretching southward to the Persian Gulf. The latter absorbed the
great monarchies of Babylonia and Assyria in the sixth century B. C.,
and extended almost from the Indus to the Mediterranean, Ægean, Euxine,
and Caspian Seas, when it had reached the summit of its power.