1. Damascus March-September, 635 Strategic Context The Rashidun Caliph Abu Bakr seeks to expand the newly established Muslim state by sending Khalid ibn al-Walid to invade Byzantine-held Levant. The Byzantine Emperor Heraclius responds by sending only a few legions to Ajnadayn before realizing the ambition of the Rashiduns and sending large detachments to push them back into the desert. However, Khalid defeats the Byzantines at the Battles of Ajnadayn and then Marj al-Suffar, forcing the remains of the Byzantine armies to take refuge in Damascus. Khalid follows and lays siege to the great city. Stakes + A Byzantine victory would frustrate Rashidun plans to annex Syria and allow Heraclius to build up superior forces to push them out. + A Rashidun victory would provide a political and military base for further conquest of Byzantine Levant. By Jonathan Webb, 2010 ©

2. Damascus, 635 Strength  Byzantines  Well  Rashiduns  Religiously motivated  Thomas  20,000  16,000  Khalid ibn al-Walid By Jonathan Webb, 2010 ©

4. Khalid does not have enough troops to completely surround the city so he divides his army into five corps to guard the gates and a mobile cavalry reserve to patrol the gaps and act as a reserve. Khalid orders each corps commander to engage Byzantine archers, repulse any sallies and seek his help if threatened. Khalid plans to simply starve out the city’s defenders. Thomas does not have enough troops to man every wall so he also concentrates his forces at the city’s gates while withholding a strong reserve. Thomas plans to defend the city and await a relief army. For the first few weeks of the siege, the two sides are inactive with the exception of a few weak sallies and sporadic archery fire initiated by Thomas as he awaits a relief army. The Byzantine garrison is elated when a relief army approaches from the northeast. Khalid sends a cavalry-heavy mobile force numbering 5,000 under Dhiraar to defeat the relief army. The ensuing battle proves difficult, forcing Khalid to detach another 4,000 troops from all sectors under cover of darkness. The Rashidun lines are dangerously thin during this time. The Rashidun detachment defeats the Byzantine relief army but Khalid can send only token forces in pursuit. The Byzantine garrison is nonetheless very demoralized and begins to pressure Thomas to negotiate peace. Thomas refuses, claiming he will soon go on the offensive and break the siege. Thomas uses archers to clear Rashidun troops away from Thomas Gate. This allows Thomas to deploy forces and lead them against Shurahbil in a strong sally. Shurahbil’s corps loses heavily but eventually repels the Byzantine attack when Thomas is wounded. During the night, Thomas again attempts to break the siege. This time, he sends minimal forces to pin Abu Ubaida and Yazid’s corps at Jabiya and Little Gate respectively. He also sends stronger forces to pin Khalid’s corps at East Gate and prevent him from coordinating an effective response. Thomas once again leads the main effort against Shurahbil’s now depleted corps. At Jabiya Gate, Abu Ubaida easily repulses the Byzantine attack. At Little Gate, Yazid struggles but the Rashidun mobile cavalry reserve intervenes, defeating the Byzantines. At East and Thomas Gate, fierce and indecisive combat causes high casualties on both sides. Khalid commits his small but effective cavalry reserve, forcing the Byzantines back through East Gate. Seeing this failure, the Byzantines attacking Shurahbil also withdraw. This defeat eliminates any chance of breaking the siege and completely demoralizes the Byzantine garrison. By ruse and with help from within the city, Khalid infiltrates East Gate with a picked group of soldiers at night and opens the gate. The rest of Khalid’s corps quickly pours through the opening and firmly establishes itself within the city. Thomas acts promptly when he sees that the city will fall by force: he sends his final reserve to slow down Khalid’s advance in the east and sends envoys to Abu Ubaida to permit his corps to enter the city in the west. The two Rashidun forces meet in the center of Damascus and begin to argue over the method of its capture. Khalid cites the fierce resistance he encountered when fighting his way to the center of the city and argues that the garrison should be destroyed. Abu Ubaida cites the peaceful envoys he received and argues the garrison should not be harmed. The other three Rashidun commanders argue that this is irrelevant; no other cities will surrender to the Rashiduns if they hear another city was guaranteed peace by any commander and then razed. Khalid acquiesces and orders that the garrison is not to be harmed. Amr Abu Ubaida Shurahbil Yazid Khalid Dhiraar Byzantines (Thomas) Rashiduns (Khalid ibn al-Walid) 20,000 Jabiya Gate Landmarks Rashiduns (Khalid) Byzantines (Thomas) 16,000 East Gate Thomas Gate Paradise GateGarden Gate Monastery Kaysan GateLittle Gate Barada River

5. Damascus, 635 Casualties & Aftermath Byzantines:Rashiduns: ? or ? or ? By Jonathan Webb, 2010 © Yazid assumed garrison command of Damascus while the Rashiduns pushed north, generally greeted as liberators; Khalid laid siege to Emesa and captured it the following spring. Meanwhile, Heraclius assembled a great army comprised of elite troops from the Byzantine capital as well as local troops. This army significantly outnumbered Rashidun forces in Syria. Khalid eventually faced this army at the Battle of Yarmuk in August 636, winning a decisive victory.

6. The Art of Battle: Animated Battle Maps http://www.theartofbattle.com By Jonathan Webb, 2010 ©