Battle of Heliopolis
640 CE.
Shown on the map at 30.129°, 31.289°.
The Battle of Heliopolis or Ayn Shams was a decisive battle in 640 between Arab Muslim armies and Byzantine Empire forces for the control of Egypt. Though there were several major skirmishes after this battle, it effectively decided the fate of the Byzantine rule in Egypt, and opened the door for the Muslim conquest of the Roman Exarchate of Africa.
Text from the Wikipedia article Battle of Heliopolis, licensed CC BY-SA 4.0.