The early Muslim conquests following the death of Muhammad in 632 CE demonstrated the success of early Islam (1). 

The Muslim empire expanded quickly through a series of conquests into non-Muslim territories. The speed at which Islam expanded is notable: “How was it that the Muslim regime in Arabia, despite limitations in manpower and other resources, conquered the Sassanid Empire and wrested several provinces from Byzantium in the course of one generation?” (2).

There are some challenges facing historical reconstructive efforts of the early conquests. They are difficult to describe, as is their chronology because of the nature of the historical sources. But where historians are fortunate, they can carefully examine Muslim sources combined with non-Muslim sources to construct something of an outline. 

The conquests had their inspiration in Muhammad himself. There were also other triggers such as small skirmishes that broke out upon Muhammad’s death when tribesmen forsook treaties negotiated by Muhammad. Historian of Islamic history Chase F. Robinson describes the connection between Muhammad and the early Muslim conquests,

“The Islamic conquest of the Near East cannot be viewed, then, as something separate from the career of Muhammad the Apostle or from the conquest of Arabia during the ridda wars. It must be seen as an organic outgrowth of Muhammad’s teachings and their impact upon Arabian society, of Muhammad’s political consolidation, pursued by traditional and novel means, and especially of his efforts to bring nomadic groups firmly under state control, and of the extension of that process of consolidation by the Islamic state and its emerging élite under the leadership of Abu Bakr” (3).

Stalwart commanders were sent out to extend and/or reinforce Islamic control (4). Caliph Abu Bakr (573-634 CE) sent Khalid ibn al-Walid (d. 642 CE) to invade Iraq. Khalid conquered Al-Hirah, aided in the conquest of Syria, captured Damascus, and combatted Byzantine armies. Shurahbil ibn Hasana (d. 639 CE) marched on the Levant to wrestle it from the Byzantines and Arfajah ibn Harthama al-Bariqi (598-654 CE) took to the seas against the mighty Persians. 

The Muslim armies were extraordinarily successful (5). In three battles in Syria, the Byzantines experienced considerable defeat. The battle of Yarmuk in 636 CE was momentous as Khalid ibn al-Walid delivered a blow to Eastern Roman emperor Heraclius’ (575-641 CE) forces which ended Byzantine rule in Syria. 

Damascus fell around 636 CE and just twenty-five years would be the capital of the caliphate. The principal cities of northern Syria followed soon after 636 CE, as did Jerusalem. From the occupation of Palestine that followed, there emerged a separate conquest movement to Egypt led by the general Al-Qa’qa’ ibn Amr al-Tamimi (d. ?). Alexandria fell in 642 CE and Muslims established their main garrison in Fustat on the edge of modern-day Cairo.

Alongside the Muslim invasions into Syria, there were conquests of Iraq. After a defeat at the battle of the Bridge in late 634 CE, a sizable Muslim army marched to the small settlement of al-Qadisiyya where, in either 636 or 637 CE, the Sasanian commander Rustam (d. 636 CE) was beaten. The Sasanians were knocked hard elsewhere too. In 637 CE, they lost at the Battle of Jalulap and then lost Ctesiphon, their capital. Consequential was the fall of Nihawand in 641 CE because the defeat of Sasanian armies there paved the way for the Islamization of Iran.

Around 640 CE, northern Mesopotamia fell to Muslim armies coming in from the Syrian desert in the west and armies marching up the Tigris from the south. In the 650s CE, control extended over the Mediterranean islands of Cyprus, Rhodes, and Crete. The general Uqba ibn Nafiy took Islamic rule to north Africa in the 660s and 670s.

A question emerges: Why were the early Muslim conquests so successful? (6) Has it to do with military numbers and combatants? Unfortunately, it is impossible to measure military figures with any accuracy. Important Christian sources exaggerate. One contemporaneous Syriac account mentions the death of 50 000 in a single battle in Syria. Another source, the Khuzistan Chronicle, dating to the 660s CE, is an anonymous Nestorian Christian text which speaks of the Muslims eliminating no fewer than 100 000 Byzantines in Egypt,

“Then God raised up against them the sons of Ishmael, [numerous] as the sand on the sea shore, whose leader (mdabbrānā) was Muḥammad (mḥmd). Neither walls nor gates, armour or shield, withstood them, and they gained control over the entire land of the Persians. Yazdgird sent against them countless troops, but the Arabs routed them all and even killed Rustam.,. The Arabs gained control of Maḥoze and all the territory. They also came to Byzantine territory, plundering and ravaging the entire region of Syria. Heraclius, the Byzantine king, sent armies against them, but the Arabs killed more than 100,000 of them” (emphasis added) (7).

Numbers provided by Muslim sources tend to be more reasonable as they put the figures in the hundreds or low thousands and such armies would be much easier to provision and manage. The Muslim forces were also probably outnumbered by their foes: “Since there is no good evidence for any substantial reduction in Byzantine manpower (and virtually no evidence at all for Sasanian numbers, reduced or otherwise), it is probably safe to assume that Muslims were often outnumbered” (8).

Muslim military success owed much to its strategic advantages over adversaries. Their armies were fast, agile, well-coordinated, and highly motivated. Such agility and coordination are very apparent in light of how quickly Islam expanded and in the short length of battles. The major, decisive battles that landed Muslims control over swathes of territory took place in the span of four or five years,

“In contrast to the large-scale, resource-intensive and protracted campaigns that were so typical of Byzantine–Sasanian warfare of the sixth and early seventh centuries, and which in at least some places resulted in widespread violence and social dislocation, the Islamic conquests of the mid-seventh century read like a series of relatively short engagements (the great battle of al-Qadisiyya is said to have lasted three days), which were made by relatively small and hit and run armies that rarely laid sieges of any length or produced casualties in large numbers” (9).

Religious belief was entangled with the conquests. The speediness in the Muslims’ military success was considered demonstrative of God’s continued participation in human affairs, especially in the Muslims through whom God conquered,

“The conquests were compelling proof that Muslims enjoyed God’s favour and generosity. What could be more persuasive than the enormous bounty of booty taken from Ctesiphon, where the Shah’s storehouses were thrown open and all manner of treasure – precious metals, vessels, garments, regalia, even foodstuffs – carried off? Arabian tribesmen were inheriting the riches of empire” (10).

The acquisition of such riches cohered with the Qur’an which made clear that God delivered bounties in this world and the next. One such bounty was dominion. But for non-Muslims, it was a different story and their view was also entangled with religious beliefs. The defeats at the hands of those the sources refer to as “Arabs”, “Saracens”, or “Hagarenes” were considered proof of God’s wrath. For both Muslims and non-Muslims, history is made as God operates through men. This view “was shared by all monotheist historians, whether Muslim or Christian, for non-Muslim monotheists the events signalled a wrathful rather than a merciful God” (11). In the 630s CE, the patriarch of Jerusalem wrote of the,

“Saracens who, on account of our sins, have now risen up against us unexpectedly and ravage all with cruel and feral design, with impious and godless audacity. More than ever, therefore, we entreat your Holiness to make urgent petitions to Christ so that he, receiving these favourably from you, may quickly quell their mad insolence and deliver these vile creatures, as before, to be the footstool of our God-given emperors” (12).

A few decades later, a chronicler in northern Mesopotamia asked: “How, otherwise, could naked men, riding without armour or shield, have been able to win, apart from divine aid, God having called them from the ends of the earth so as to destroy, by them, “a sinful kingdom” [i.e. Byzantium] and to bring low, through them, the proud spirit of the Persians?” (13).

The Muslims did not always meet success later. The first great civil war of the 650s CE broke out and was believed to demonstrate God’s disfavor. Disunity among Muhammad’s successors followed.

References

1. Robinson, Chase F. 2010. The New Cambridge History of Islam: Volume 1, The Formation of the Islamic World, Sixth to Eleventh Centuries. Cambridge University Press.

2. Jandora, J. W. 1986. “Developments in Islamic Warfare: The Early Conquests”. Studia Islamica 64:101-113. p. 101

3. Donner, Fred. 1981. The Early Islamic Conquests. Princeton University Press. p. 90

4. Robinson, Chase F. 2010. Ibid. p. 196

5. Robinson, Chase F. 2010. Ibid. p. 196

6. Robinson, Chase F. 2010. Ibid. p. 197

7. Hoyland, Robert. 1997. Seeing Islam as Others Saw It: A Survey and Evaluation of Christian, Jewish and Zoroastrian Writings on Early Islam. Darwin Press. p. 304 (Scribd ebook format)

8. Robinson, Chase F. 2010. Ibid. p. 197.

9. Robinson, Chase F. 2010. Ibid. p. 197-198

10. Robinson, Chase F. 2010. Ibid. p. 201

11. Robinson, Chase F. 2010. Ibid. p. 201

12. Hoyland, Robert. 1997. Ibid. p. 110-111

13. Robinson, Chase F. 2010. Ibid. p. 201-2002