Battle of Ullais
633 CE.
Shown on the map at 31.618°, 44.570°.
The Battle of Ullais (Arabic: معركة أليس) was fought between the forces of the Rashidun Caliphate and the Sasanian Persian Empire in the middle of June 633 AD in Iraq, and is sometimes referred to as the Battle of Blood River since, as a result of the battle, there were enormous amounts of Persian Sasanian and Arab Christian casualties. This was now the last of four consecutive battles that were fought between invading Muslims and the Persian army. After each battle the Persians and their allies regrouped and fought again. These battles resulted in the retreat of the Sasanian Persian army from Iraq and its capture by Muslims under the Rashidun Caliphate.
Text from the Wikipedia article Battle of Ullais, licensed CC BY-SA 4.0.