Siege of Ctesiphon
629 CE.
Shown on the map at 33.094°, 44.581°.
The siege of Ctesiphon took place on 27 April 629 between the forces of Shahrbaraz and Ardashir III. Shahrbaraz managed to capture Ctesiphon with a small force, revealing to all the weakness of the Sasanian Empire.
Text from the Wikipedia article Siege of Ctesiphon (629), licensed CC BY-SA 4.0.