page_title: Rashidun Caliphate
section_title: Conquest of Byzantine Syria
hierarchical_section_title: Rashidun Caliphate / History / Military expansion / Wars against the Byzantine Empire / Conquest of Byzantine Syria
context_page_description: The Rashidun Caliphate was the first of the four major caliphates established after the death of the Islamic prophet Muhammad. It was ruled by the first four successive caliphs of Muhammad after his death in 632 CE. These caliphs are collectively known in Sunni Islam as the Rashidun, or "Rightly Guided" caliphs. This term is not widely used in Shia Islam as Shia Muslims do not consider the rule of the first three caliphs as legitimate.
  The Rashidun Caliphate is characterized by a twenty-five year period of rapid military expansion, followed by a five-year period of internal strife.
  The Rashidun Army at its peak numbered more than 100,000 men. By the 650s, the caliphate in addition to the Arabian Peninsula had subjugated the Levant, to the Transcaucasus in the north; North Africa from Egypt to present-day Tunisia in the west; and the Iranian plateau to parts of Central Asia and South Asia in the east.
  The caliphate arose out of the death of Muhammad in 632 CE and the subsequent debate over the succession to his leadership. Abu Bakr, a close companion of Muhammad from the Banu Taym clan, was elected the first Rashidun leader and began the conquest of the Arabian Peninsula.
context_section_description: After Khalid consolidated his control of Iraq, Abu Bakr sent four armies to Syria on the Byzantine front under four different commanders: Abu Ubaidah ibn al-Jarrah (acting as their supreme commander), Amr ibn al-As, Yazid ibn Abu Sufyan and Shurhabil ibn Hasana. However, their advance was halted by a concentration of the Byzantine army at Ajnadayn. Abu Ubaidah then sent for reinforcements. Abu Bakr ordered Khalid, who by now was planning to attack Ctesiphon, to march from Iraq to Syria with half his army. There were 2 major routes to Syria from Iraq, one passing through Mesopotamia and the other through Daumat ul-Jandal. Khalid took an unconventional route through the Syrian Desert, and after a perilous march of 5 days, appeared in north-western Syria.
  The border forts of Sawa, Arak, Tadmur, Sukhnah, al-Qaryatayn and Hawarin were the first to fall to the invading Muslims. Khalid marched on to Bosra via the Damascus road. At Bosra, the Corps of Abu Ubaidah and Shurhabil joined Khalid, upon which, per Abu Bakr's orders, Khalid assumed overall command from Abu Ubaidah. Bosra, caught unprepared, surrendered after a brief siege in July 634 (see Battle of Bosra), effectively ending the dynasty of the Ghassanids.
  From Bosra, Khalid sent orders to the other corps commanders to join him at Ajnadayn, where, according to early Muslim historians, a Byzantine army of 90,000 (modern sources state 9,000) was concentrated to push back the Muslims. The Byzantine army was defeated decisively on 30 July 634 in the Battle of Ajnadayn. It was the first major pitched battle between the Muslims and Byzantines and cleared the way for the former to capture central Syria. Damascus, the Byzantine stronghold, was conquered shortly after on 19 September 634. The Byzantine army was given a deadline of 3 days to flee as far as they could, with their families and treasure, or simply agree to stay in Damascus and pay tribute.  After the three days had passed, the Muslim cavalry, under Khalid's command, attacked the Roman army by catching up to them using an unknown shortcut at the battle of Maraj-al-Debaj.
  On 22 August 634, Abu Bakr died, making Umar his successor. As Umar became caliph, he restored Abu Ubaidah ibn al-Jarrah to the overall command of the Muslim armies. The conquest of Syria slowed down under him while he relied heavily on the advice of Khalid, who he kept close at hand.
  The last large garrison of the Byzantine army was at Fahl, which was joined by survivors of Ajnadayn. With this threat at their rear the Muslim armies could not move further north nor south, thus Abu Ubaidah decided to deal with the situation, and defeated and routed this garrison at the Battle of Fahl on 23 January 635, which proved to be the "Key to Palestine". After this battle Abu Ubaidah and Khalid marched north towards Emesa; Yazid was stationed in Damascus while Amr and Shurhabil marched south to capture Palestine.
  While the Muslims were at Fahl, sensing the weak defense of Damascus, Emperor Heraclius sent an army to re-capture the city. This army, however, could not make it to Damascus and was intercepted by Abu Ubaidah and Khalid on their way to Emesa. The army was destroyed in the battle of Maraj-al-Rome and the second battle of Damascus. Emesa and the strategic town of Chalcis made peace with the Muslims for one year in order to buy time for Heraclius to prepare his defences and raise new armies. The Muslims welcomed the peace and consolidated their control over the conquered territory. However, as soon as the Muslims received the news of reinforcements being sent to Emesa and Chalcis, they marched against Emesa, laid siege to it and eventually captured the city in March 636.
  The prisoners taken in the battle informed them about Emperor Heraclius's plans to take back Syria. They said that an army possibly 200,000 strong would soon emerge to recapture the province. Khalid stopped here on June 636. As soon as Abu Ubaida heard the news of the advancing Byzantine army, he gathered all his officers to plan their next move. Khalid suggested that they should consolid
caption: Map detailing the route of the Muslim invasion of northern Syria
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