The Rashidun Caliphate conquered Byzantine Syria between 634–638 CE as part of the Arab–Byzantine wars and the wider Muslim conquests.
Clashes between the Muslims and the Byzantines on the southern Levantine borders of the Byzantine Empire had occurred previously during the lifetime of Muhammad, with the Battle of Mu'tah in 629 CE. However, the actual conquest did not begin until 634, two years after Muhammad's death. It was led by the first two Rashidun caliphs who succeeded Muhammad: Abu Bakr and Umar. During this time, Khalid ibn al-Walid was the most important commander of the Rashidun army. In the aftermath of the conquest, Syria was brought under Arab Muslim rule and developed into the provincial region of Bilad al-Sham.
Background
Byzantine Syria
Syria had been under Roman rule for seven centuries prior to the Arab Muslim conquest and had been invaded by the Persian Sasanian Empire on a number of occasions during the 3rd, 6th and 7th centuries; it had also been subject to raids by the Sasanian Empire' Arab allies, the Lakhmids. During the Roman period, beginning after the Siege of Jerusalem in the year 70, the Levant (Judea, Samaria, and the Galilee) was renamed Palaestina, subdivided into Diocese I and II. The Romans also renamed an area of land including the Negev, Sinai, and the west coast of the Arabian Peninsula as Palaestina Salutaris, sometimes called Palaestina III or Palaestina Tertia. Part of the area was ruled by the Arab vassal state of the Ghassanids' symmachos.
During the last of the Roman-Persian Wars, beginning in 602, the Persians under Khosrau II had succeeded in occupying Syria, Palestine and Egypt for over a decade before being forced by the victories of Heraclius to conclude the peace of 628. Thus, on the eve of the Muslim conquests the Romans (or Byzantines as modern Western historians conventionally refer to Romans of this period) were still in the process of rebuilding their authority in these territories, which in some areas had been lost to them for almost twenty years. Politically, the Syrian region consisted of two provinces: Syria proper stretched from Antioch and Aleppo in the north to the top of the Dead Sea. To the west and south of the Dead Sea lay the province of Palestine.
Byzantine Syria was mostly home to Aramaic and Greek speakers and a partly Arab population, especially in its eastern and southern parts. The Ghassanid tribe, who migrated from Yemen to Syria, converted to Christianity and served as foederati for the Eastern Roman empire like the Tanukh before them. Thereafter, they ruled a semi-autonomous state with their own king under Roman vassalage. The Ghassanid dynasty became one of the honoured princely dynasties of the Empire, with the Ghassanid king ruling over the Arabs in Jordan and Southern Syria from his capital at Bostra. The last of the Ghassanid kings, who ruled at the time of the Muslim invasion, was Jabala ibn al-Ayham.
The Byzantine Emperor Heraclius, after re-capturing Syria from the Sassanians, set up new defense lines from Gaza to the south end of the Dead Sea. These lines were only designed to protect communications from bandits, and the bulk of the Byzantine defenses were concentrated in Northern Syria facing the traditional foes, the Sassanid Persians. The drawback of this defense line was that it enabled the Muslims, advancing from the desert in the south, to reach as far north as Gaza before meeting regular Byzantine troops.
The 7th century was a time of rapid military change in the Byzantine Empire. The empire was certainly not in a state of collapse when it faced the new challenge from Arabia after being exhausted by recent Roman–Persian Wars, but utterly failed to tackle the challenge effectively.
Rise of the Caliphate
Military confrontations with the Byzantine Empire began during the lifetime of Muhammad. The Battle of Mu'tah was fought in September 629 near the village of Mu'tah, east of the Jordan River and Karak in Karak Governorate, between the forces of the Islamic prophet Muhammad and the forces of the Byzantine Empire and their Arab Christian Ghassanid vassals. In Islamic historical sources, the battle is usually described as the Muslims' attempt to take retribution against the Ghassanids after a Ghassanid official executed Muhammad's emissary who was en route to Bosra. During the battle the Muslim army was routed. After three Muslim leaders were killed, the command was given to Khalid ibn al-Walid and he succeeded in saving the rest of the forces. The surviving Muslim forces retreated to Medina.
After the Farewell Pilgrimage in 632, Muhammad appointed Usama ibn Zayd as the commander of an expeditionary force which was to invade the region of Balqa in the Byzantine Empire. This expedition was known as the Expedition of Usama bin Zayd and its stated aim was to avenge the Muslim losses at the Battle of Mu'tah, in which Usama's father and Muhammad's former adopted son, Zayd ibn Harithah, had been killed. Usama's expedition in May/June 632 was successful and his army was the first Muslim force to successfully invade and raid Byzantine territory.
Muhammad died in June 632, and Abu Bakr was appointed Caliph and political successor at Medina. Soon after Abu Bakr's succession, several Arab tribes revolted against him in the Ridda wars (Arabic for the Wars of Apostasy). The Campaign of the Apostasy was fought and completed during the eleventh year of the Hijri. The year 12 Hijri dawned, on 18 March 633, with Arabia united under the central authority of the Caliph at Medina.
Whether Abu Bakr intended a full-out imperial conquest or not is hard to say; he did, however, set in motion a historical trajectory that in just a few short decades would lead to one of the largest empires in history, starting with a confrontation with the Persian Empire under the general Khalid ibn al-Walid.
Historiography
Despite the often contradictory early Islamic narratives of the conquest, the historian Fred Donner deemed it "possible to reconstruct the broad outlines" of the war. The course of the conquest is generally divided into three main phases. During the initial invasion in late 633–early 634, Muslim forces encountered local garrisons and conquered much of the southern, tribal Syrian countryside. The second phase in 634–636 saw the arrival of the prominent Arab general Khalid ibn al-Walid and the capture of major towns, eliciting increasingly stronger responses by the Byzantine emperor. In the ensuing major battles, the Byzantine imperial armies were decisively defeated. This breaking of imperial power in the region brought about the final phase, the occupation of Syria, from 637 to 647–648. This stage, in Donner's words, entailed "the rapid conquest of the remaining countryside not under the Muslims' control, especially in northern Syria, and the piecemeal reduction of individual Syrian towns, which had been left alone to resist the advancing Muslims".
Initial invasion
With the tribes of Arabia brought under Medina's control during the Ridda wars, Abu Bakr prepared and dispatched armies for the conquest of Byzantine Syria. The first of these armies was probably that of Khalid ibn Sa'id ibn al-As, an early companion of Muhammad. He was shortly after dismissed at the instigation of Umar for having opposed Abu Bakr's succession, with one set of early Muslim accounts placing this dismissal before his departure from Medina and the other once he reached the Tayma oasis on the approaches to Syria. At Tayma, he was supposedly reinforced with troops led by the commander al-Walid ibn Uqba, engaged with Arab allies of the Byzantines, and was eventually defeated.
In the Islamic calendar date of Rajab 12 AH (September 633) or the beginning of 13 AH (Spring 634), Abu Bakr dispatched three or four armies to Syria led respectively by Amr ibn al-As, Shurahbil ibn Hasana, Yazid ibn Abi Sufyan, and Abu Ubayda ibn al-Jarrah, all of whom were companions of Muhammad and the first two veterans of the Ridda wars. The timing and order of each commander's deployment and whether they were independent of each other or if any held the high command at this stage is not clear. Each army took a separate route toward Syria. Amr embarked on the coastal road to Ayla before breaking northwest into the Negev Desert and toward Gaza. The other commanders took the road through Tabuk, with Shurahbil stopping in the area east of the Arabah Valley, Yazid terminating in the Balqa region east of the Dead Sea, and Abu Ubayda taking up position in the Golan Heights area. The 9th-century historian al-Baladhuri and modern scholarship in general dates Abu Ubayda's arrival in Syria to after Abu Bakr's death in 634 and as late as 636.
According to narrative of the 8th-century historian al-Azdi, Abu Bakr instructed Yazid with ethical and operational instructions:
When you meet the enemy, and God leads you to victory, do not manacle, mutilate, maim, or betray, and do not accuse [the defeated] of cowardice. Do not, you all, kill children, old men, or women; do not burn palm trees or uproot them; do not cut down fruitful trees; and do not slaughter cattle except for eating [them]. You will pass by people in their hermitages who claim to have secluded themselves for [worshipping] God; leave them to what they have secluded themselves for. You will also find others in the middle of whose heads Satan has taken up abode, as if the middles of their heads were the sandgrouse's nests (afahīs al-qatā). Strike the nests which they have hollowed in their heads with swords until they turn repentantly to Islam, or until they bring tribute by hand and with humility. God will certainly support those who support Him and His Messengers in absentia (bi-al-ghayb).
The authenticity of these instructions has been questioned by modern scholars. James Moreton Wackeley characterises it as a literary construct intended to idealise early Muslim leadership, while Albrecht Noth interprets such speeches as part of a wider tradition in which later transmitters reworked existing material to promote moral and legal norms, retroactively ascribing it to prominent early figures to strengthen its authority. Such interpretations are situated within a broader secular academic discourse that applies historical-critical methods to the Islamic tradition.
The first encounter between the Muslims and Byzantines occurred at Dathin and Badan, near Gaza, where negotiations between Amr and the local Byzantine garrison commander broke down and gave way to a skirmish ending with Amr's defeat of the local garrison. While of minor consequence, news of the Arabs' victory at Dathin alerted the Byzantines to the entry of Muslim forces into Syria. Amr afterward set up headquarters at Ghamr al-Arabat, a location in the middle of the Arabah Valley. Credible details of the other commanders' activities is sparse, but a lieutenant of Abu Ubayda may have gained the surrender of a town called Ma'ab in the Balqa, Yazid may have succeeded against a Byzantine force in a minor clash in Palestine and Shurahbil oversaw activity against the pro-Byzantine Quda'a tribal group in his area of operations.
Donner concludes that the operations in this phase of the Muslim campaigns, where urban centers and major agricultural areas were avoided, targeted the territories inhabited by nomadic and partly settled Arab tribes. Kennedy comments that at this point, "the Muslim attacks on Syria had amounted to little more than pinpricks along the frontiers". The goal of the Muslim state was probably to continue the process of subjugating all Arab tribes, which Medina had consistently viewed as posing threats to its power. Once the bulk of the tribes were under Muslim control, the Muslims could launch the major assaults against Syria's main armies and cities.