Battle of Dayr al-Jamajim
701 CE.
Shown on the map at 32.033°, 44.400°.
The Battle of Dayr al-Jamajim ("Battle of the Monastery of Skulls" after a nearby Nestorian monastery), was fought in 701 CE in central Iraq between the largely Syrian Umayyad army under al-Hajjaj ibn Yusuf against the mostly Iraqi followers of Abd al-Rahman ibn Muhammad ibn al-Ash'ath, who had rebelled against al-Hajjaj's overbearing attitude towards the Iraqis.
Text from the Wikipedia article Battle of Dayr al-Jamajim, licensed CC BY-SA 4.0.