Bound by the Tigris and Euphrates rivers is Mesopotamia (aka the Euphrates Valley), which in antiquity entailed Akkad to the north and Sumer to the south, and later Assyria to the north and Babylonia to the south ^1:1. The first permanent Mesopotamian settlements formed in the 5^th millennium BC, then flourished in the 4^th millennium BC to form the empires of Akkad and Sumer. Later, Mesopotamia was dominated by Assyria and Babylonia. Romans misleadingly labeled all of Mesopotamia as Chaldea. In fact, Chaldea was a small part of southern Mesopotamia that accrued power and territory to form Neo-Babylonia (625-539 BC) ^2:1.

Mesopotamia was the cradle of civilization due to the convergence of three factors: riverine trade; hospitable climate; and fertile soil. The Euphrates River (aka Purattu or the great river) was a very docile river. However, the agility of the Tigris River (aka Idiklat or the rapid) gave it command over riverine trade ^2:5&7. In northern Assyria, the Kurdish mountains run near the Tigris below Mosul (ancient Nineveh). The temperate climate there is much like Western Europe ^1:4. In southern Assyria, the mountains of the north give way to unbroken alluvial plains with unrelenting heat and minimal rain. Continuing further south into northern Babylonia, a Mediterranean climate returns and the river banks of Baghdad (near Babylon) were lined with palms. In southern Babylonia, the land is mostly consumed by marshes riddled with reeds. Winter rains swell the Tigris and its tributaries, causing fatal annual floods while leaving behind fertile soil deposits ^1:3;2:7. A flood not only destroyed what was in its path, but due to the loose alluvial soil could cause the river to change its watercourse (a catastrophic event for a riverside settlement) ^1:4. Rampant flooding was overcome by canals that defused the riverine deluge, irrigated the soil and provided navigable waterways.