Siege of Ctesiphon
637 CE.
Shown on the map at 33.094°, 44.581°.
The siege of Ctesiphon took place from January to March 637, shortly after the Rashidun Caliphate defeated the Sasanian Empire in the Battle of al-Qadisiyyah. As it had served as the Persian capital city since the Parthian period, the Rashidun victory at Ctesiphon was one of the most significant events of the Muslim conquest of Persia; Muslim rule was consolidated over all of Mesopotamia. The victory of the Rashidun army during this siege also set the stage for further Muslim invasions of the Persian mainland, where the Sasanian army found itself confined.
Text from the Wikipedia article Siege of Ctesiphon (637), licensed CC BY-SA 4.0.