Suzanne S. answered 06/09/19
ACT_SAT_GRE, English, Reading, Doctoral Dissertations
Your answer was close; however, the Ancient History Encyclopedia, under “War in Ancient Times,” goes a bit farther back. The article states, “The first war in recorded history took place in Mesopotamia in 2700 BCE between Sumer and Elam. The Sumerians, under command of the King of Kish, Enembaragesi, defeated the Elamites in this war and, it is recorded, ‘carried away as spoils the weapons of Elam.’” The articles goes on to discuss the differences among earlier and later skirmishes, but for your purposes, 2700 BCE answers your question. I assume you are studying World History.