Siege of Emesa
638 CE.
Shown on the map at 34.723°, 36.715°.
The siege of Emesa in 638 was laid by a coalition force of Arab Christian tribes from Jazira which was mustered by Heraclius in an attempt to stem the losses of Byzantine territories due to the rapid expansion of the Rashidun Caliphate in the Levant.
Text from the Wikipedia article Siege of Emesa (638), licensed CC BY-SA 4.0.