Lower Mesopotamia Lower Mesopotamia Lower Mesopotamia is a historical region of Iraq. Also known as the Sawad and al-'Irāq al-'Arabi ("Arabian Irāq") in the Middle Ages. Lower Mesopotamia was home to ancient Sumerian and Babylonian civilisations. An alluvial plain begins north of Baghdad and extends to the Persian Gulf. Here the Tigris and Euphrates rivers lie above the level of the plain in many places, and the whole area is a river delta interlaced by the channels of the two rivers and by irrigation canals. Intermittent lakes, fed by the rivers in flood, also characterize southeastern Iraq. A fairly large area ()
Mesopotamia (theme) Mesopotamia (theme) Mesopotamia () was the name of a Byzantine theme (a military-civilian province) located in what is today eastern Turkey. It should not be confused with the region of Mesopotamia or with the older Roman and early Byzantine province of Mesopotamia. The Byzantine theme was located between the rivers Arsanias (modern Murat) and Çimisgezek. The theme was formed probably between 899 and 911, when Emperor Leo VI the Wise (r. 886–912) appointed the former "strategos" of the Charsianon, named Orestes, as its governor. Most of the province was formed out the Armenian principality of Takis, ruled by the chieftain