page_title: Battle of Opis
section_title: Battle
hierarchical_section_title: Battle of Opis / Battle
context_page_description: The Battle of Opis, fought in September 539 BC, was a major engagement between the armies of Persia under Cyrus the Great and the Neo-Babylonian Empire under Nabonidus during the Persian invasion of Mesopotamia. At the time, Babylonia was the last major power in western Asia that was not yet under Persian control. The battle was fought in or near the strategic riverside city of Opis, north of the capital Babylon. It resulted in a decisive victory for the Persians. A few days later, the city of Sippar surrendered to the Persians and Cyrus's forces entered Babylon apparently without a fight. Cyrus was subsequently proclaimed king of Babylonia and its subject territories, thus ending the independence of Babylon and incorporating the Babylonian Empire into the greater Persian Empire.
context_section_description: The Nabonidus Chronicle records that the battle took place in the month of Tashritu (27 September-27 October) "at Opis on the [bank of the] Tigris". Very little is known about the events of the battle; the chronicle does not provide any details of the battle's course, the disposition of the forces on either side or the casualties inflicted. The Persian army under Cyrus fought "the army of Akkad" (meaning the Babylonians in general, not the city of that name). The identity of the Babylonian commander is not recorded in the chronicle but it has traditionally been assumed that Belshazzar, the son of Nabonidus, was in command. His fate is unclear and he may have been killed in the battle.
  The outcome of the battle was clearly a Babylonian defeat, possibly a rout, as the defeated Babylonian army is not mentioned again in the chronicle. Following the battle the Persian forces "took plunder" from the defeated Babylonians. Most translations of the Chronicle also refer to a "massacre" of "the people of Akkad", though translators disagree on which side was responsible and who was killed – the population of Opis or the retreating Babylonian army.
  In Pierre Briant's view, "This victory was followed by an immense haul of booty and the massacre of those who attempted to resist." Andrew Robert Burn comments: "Indeed on one reading of the text, Akkad broke out into open revolt, and Nabonidus' last military achievement was slaughter of rebels." Maria Brosius interprets the massacre as a punitive action, "mak[ing] an example of a city trying to resist the Persian army". Cuyler Young comments on the Chronicle accounts: "This reference in the Chronicle suggests that the Persians captured intact the main camp of Nabonidus' army and that, as is so often the case, the real killing of the engagement came after the Babylonians had fallen prey to fear and panic and had retreated from the field." Amélie Kuhrt comments that the references to a massacre and looting suggest that the battle was "probably a hard-won victory". W. G. Lambert argues a contrarian view that there was no massacre or slaughter at all.
  The battle is not mentioned in the inscription on the Cyrus Cylinder, which portrays Cyrus as liberating Babylon peacefully and with the consent of its people. However, the battle demonstrates that the existing Babylonian regime actively resisted Cyrus's invasion of Mesopotamia.
caption: Route of the Persian invasion of Babylonia, September–October 539 BC