Battle of Ullais

This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages) This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Battle of Ullais" – news · newspapers · books · scholar · JSTOR (April 2008) (Learn how and when to remove this message) This article's factual accuracy is disputed. Relevant discussion may be found on the talk page. Please help to ensure that disputed statements are reliably sourced. (April 2008) (Learn how and when to remove this message) (Learn how and when to remove this message)

Battle of Ullais
Part of Muslim conquest of Persia
Overview of the region where the Battle of Ullais was fought, showing the river Euphrates and its tributary the Khaseef (Iraq)
Date May 633 A.D. Location Sasanian Mesopotamia (modern Iraq) 31°37′4.001″N 44°34′10.999″E / 31.61777806°N 44.56972194°E / 31.61777806; 44.56972194 Result Rashidun victory
Belligerents
Rashidun Caliphate	Sasanian Empire Arab allies
Commanders and leaders
Khalid ibn al-Walid Al-Muthanna ibn Haritha	Jaban Abdul-Aswad † Abjar †
Strength
18,000[1]	70,000 (Primary Arab sources) 30,000[2] (modern estimation)
Casualties and losses
~2,000[2]	70,000 killed (Primary Arab sources)[3][4][5]
class=notpageimage| Location within Iraq

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.