Babylonia, ancient empire of Mesopotamia. The name is sometimes given to the whole civilization of S Mesopotamia, including the states established by the city rulers of Lagash, Akkad (or Agade), Uruk, and Ur in the 3d millennium B.C. Historically it is limited to the first dynasty of Babylon established by Hammurabi (c.1750 B.C.), and to the Neo-Babylonian period after the fall of the Assyrian Empire. Hammurabi, who had his capital at Babylon, issued the code of laws for the management of his large empire—for he was in control of most of the Tigris and Euphrates region even before he defeated the Elamites. Babylonian cuneiform writing was derived from the Sumerians. The quasifeudal society was divided into classes—the wealthy landowners and merchants and the priests; the less wealthy merchants, peasants, and artisans; and the slaves. The Babylonian religion (see Middle Eastern religions) was inherited from the older Sumerian culture. All these Babylonian institutions influenced the civilization of Assyria and so contributed to the later history of the Middle East and of Western Europe.

The wealth of Babylonia tempted nomadic and seminomadic neighbors; even under Hammurabi's successor Babylonia was having to stave off assaults. Early in the 18th cent. B.C. the Hittites sacked Babylon and held it briefly. The nomadic Kassites (Cassites), a tribe from Elam, took the city shortly thereafter and held it precariously for centuries. Babylonia degenerated into anarchy c.1180 B.C. with the fall of the Kassites. As a subsidiary state of the Assyrian Empire (after the 9th cent. B.C.), Babylonia flourished once more. It was the key area in the attempted uprising against the Assyrian king, Sennacherib, and Babylon was sacked (c.689 B.C.) in his reign.

After the death of Assurbanipal, the last great Assyrian monarch, Nabopolassar, the ruler of Babylonia, established (625 B.C.) his independence. He allied himself with the Medes and Persians and helped to bring about the capture of Nineveh (612 B.C.) and the fall of the Assyrian Empire. He established what is generally known as the Chaldaean or New Babylonian Empire. Under his son, Nebuchadnezzar, the new empire reached its height (see Babylon). The recalcitrant Hebrews were defeated and punished with the Babylonian captivity. Egypt had already been defeated by Nebuchadnezzar in the great battle of Carchemish (605) while Nabopolassar was still alive. The empire seemed secure, but it was actually transitory. The steady growth of Persian power spelled the end of Babylonia, and in 538 B.C. the last of the Babylonian rulers surrendered to Cyrus the Great (see also Belshazzar). Babylonia became an important region of the Persian Empire.

Ancient cultural region of the Tigris and Euphrates river system. The area was divided into Sumer (southeast) and Akkad (northwest) when the first Babylonian line of Amorite kings took power after 2000 BC. Largely because of the efforts of Hammurabi (r. circa 1792–50 BC), Babylonia gained regional hegemony but declined after his death; the Kassites from the east eventually assumed power (circa 1595) and established a dynasty that lasted some four centuries. After Elam conquered Babylonia (circa 1157 BC), a series of wars established a new Babylonian dynasty whose outstanding member was Nebuchadrezzar I (r. circa 1124–03 BC). Following his rule, a three-way struggle developed for control of Babylonia among Assyria, Aram (see Aramaeans), and Chaldea, in which the Assyrians ruled the area most frequently (9th–7th century BC). In the 7th–6th century BC the Chaldean Nebuchadrezzar II (605–562 BC) instituted the last and greatest period of Babylonian supremacy, conquering Syria and Palestine and rebuilding Babylon, the capital city. It was conquered in 539 BC by the Persian Achaemenian dynasty under Cyrus II and in 331 BC by Alexander the Great, after which the capital city was gradually abandoned.

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