Early Muslim conquests

Background

The prolonged and escalating Byzantine–Sassanid wars of the 6th and 7th centuries and the recurring outbreaks of bubonic plague (Plague of Justinian) left both empires exhausted and vulnerable in the face of the sudden emergence and expansion of the Arabs. The last of these wars ended with victory for the Byzantines: Emperor Heraclius regained all lost territories, and restored the True Cross to Jerusalem in 629.

Nevertheless, neither empire was given any chance to recover, as within a few years they were struck by the onslaught of the Arabs (newly united by Islam), which, according to Howard-Johnston, "can only be likened to a human tsunami". According to George Liska, the "unnecessarily prolonged Byzantine–Persian conflict opened the way for Islam".

In late 620s Muhammad had already managed to conquer and unify much of Arabia under Muslim rule, and it was under his leadership that the first Muslim-Byzantine skirmishes took place. Just a few months after Heraclius and the Persian general Shahrbaraz agreed on terms for the withdrawal of Persian troops from occupied Byzantine eastern provinces in 629, Arab and Byzantine troops confronted each other at the Mu'tah. Muhammad died in 632 and was succeeded by Abu Bakr, the first Caliph with undisputed control of the entire Arab peninsula after the successful Ridda wars, which resulted in the consolidation of a powerful Muslim state throughout the peninsula.

Conquest of Syria: 634–641

The province of Syria was the first to be wrested from Byzantine control. Arab-Muslim raids that followed the Ridda wars prompted the Byzantines to send a major expedition into southern Palestine, which was defeated by the Arab forces under command of Khalid ibn al-Walid at the Battle of Ajnadayn (634). On the heels of their victory, the Arab armies took Damascus in 636, with Baalbek, Homs, and Hama to follow soon afterwards. However, other fortified towns continued to resist despite the rout of the imperial army and had to be conquered individually. Jerusalem fell in 638, Caesarea in 640, while others held out until 641.

Conquest of Egypt: 639–642

The Byzantine province of Egypt held strategic importance for its grain production, naval yards, and as a base for further conquests in Africa. The Muslim general 'Amr ibn al-'As began the conquest of the province on his own initiative in 639. The Arab forces won a major victory at the Battle of Heliopolis (640), but they found it difficult to advance further because major cities in the Nile Delta were protected by water and because they lacked the machinery to break down city fortifications. Nevertheless, the province was scarcely urbanized and the defenders lost hope of receiving reinforcements from Constantinople when the emperor Heraclius died in 641. The last major center to fall into Arab hands was Alexandria, which capitulated in 642. According to Hugh Kennedy, "Of all the early Muslim conquests, that of Egypt was the swiftest and most complete. [...] Seldom in history can so massive a political change have happened so swiftly and been so long lasting."

Conquest of Mesopotamia and Persia: 633–651

After an Arab incursion into Sasanian territories, the energetic king Yazdgerd III, who had just ascended the Persian throne, raised an army to resist the invasion. However, the Persians suffered a devastating defeat at the Battle of al-Qadisiyyah in 636. As a result, the Arab-Muslims gained control over the whole of Iraq, including Ctesiphon, the capital city of the Sassanids. The Persian forces withdrew over the Zagros mountains and the Arab army pursued them across the Iranian plateau, where the fate of the Sasanian Empire was sealed at the Battle of Nahavand (642). As the conquerors slowly covered the vast distances of Iran punctuated by hostile towns and fortresses, Yazdgerd III retreated, finally taking refuge in Khorasan, where he was assassinated by a local satrap in 651. In the aftermath of their victory over the imperial army, the invaders still had to contend with a collection of militarily weak but geographically inaccessible principalities of Persia. It took decades to bring them all under control of the caliphate.

Explanations of success of the early conquests

The rapidity of the early conquests has received various explanations. Contemporary Christian writers conceived them as God's punishment visited on their fellow Christians for their sins. Early Muslim historians viewed them as a reflection of religious zeal of the conquerors and evidence of divine favor. The theory that the conquests are explainable as an Arab migration triggered by economic pressures enjoyed popularity early in the 20th century, but has largely fallen out of favor among historians, especially those who distinguish the migration from the conquests that preceded and enabled it.

There are indications that the conquests started as initially disorganized pillaging raids launched partly by non-Muslim Arab tribes in the aftermath of the Ridda wars, and were soon extended into a war of conquest by the Rashidun caliphs, although other scholars argue that the conquests were a planned military venture already underway during Muhammad's lifetime. Fred Donner writes that the advent of Islam "revolutionized both the ideological bases and the political structures of the Arabian society, giving rise for the first time to a state capable of an expansionist movement." According to Chase F. Robinson, it is likely that Muslim forces were often outnumbered, but, unlike their opponents, they were fast, well coordinated and highly motivated.

Another key reason was the weakness of the Byzantine and Sasanian empires, caused by the wars they had waged against each other in the preceding decades with alternating success. It was aggravated by a plague that had struck densely populated areas and impeded conscription of new imperial troops, while the Arab armies could draw recruits from nomadic populations. The Sasanian empire, which had lost the latest round of hostilites with the Byzantines was also affected by a crisis of confidence, and its elites suspected that the ruling dynasty had forfeited favor of the gods. The Arab military advantage was increased when Christianized Arab tribes who had served imperial armies as regular or auxiliary troops switched sides and joined the west-Arabian coalition. Arab commanders also made liberal use of agreements to spare lives and property of inhabitants in case of surrender and extended exemptions from paying tribute to groups who provided military services to the conquerors. Additionally, the Byzantine persecution of Christians opposed to the Chalcedonian creed in Syria and Egypt alienated elements of those communities and made them more open to accommodation with the Arabs once it became clear that the latter would let them practice their faith undisturbed as long as they paid tribute.

The conquests were further secured by the large-scale migration of Arabian peoples into the conquered lands which followed the conquests. Robert Hoyland argues that the failure of the Sasanian empire to recover was due in large part to the geographically and politically disconnected nature of Persia, which made coordinated action difficult once the established Sasanian rule collapsed. Similarly, the difficult terrain of Anatolia made it difficult for the Byzantines to mount a large-scale attack to recover the lost lands, and their offensive action was largely limited to organizing guerrilla operations against the Arabs in the Levant.

Conquest of Sindh: 711–714

Although there were sporadic incursions by Arab generals in the direction of India in the 660s and a small Arab garrison was established in the arid region of Makran in the 670s, the first large-scale Arab campaign in the Indus valley occurred when the general Muhammad bin Qasim invaded Sindh in 711 after a coastal march through Makran. Three years later the Arabs controlled all of the lower Indus valley. Most of the towns seem to have submitted to Arab rule under peace treaties, although there was fierce resistance in other areas, including by the forces of Raja Dahir at the capital city Debal. Arab incursions southward from Sindh were repulsed by armies of Gurjara and Chalukya kingdoms, and further Islamic expansion was checked by the Rashtrakuta empire, which gained control of the region shortly after.

Conquest of the Maghreb: 647–742

Arab forces began launching sporadic raiding expeditions into Cyrenaica (modern northeast Libya) and beyond soon after their conquest of Egypt. Byzantine rule in northwest Africa at the time was largely confined to the coastal plains, while autonomous Berber polities controlled the rest. In 670 Arabs founded the settlement of Qayrawan, which gave them a forward base for further expansion. Muslim historians credit the general Uqba ibn Nafi with subsequent conquest of lands extending to the Atlantic coast, although it appears to have been a temporary incursion. The Berber chief Kusayla and an enigmatic leader referred to as Kahina (prophetess or priestess) seem to have mounted effective, if short-lived resistance to Muslim rule at the end of the 7th century, but the sources do not give a clear picture of these events. Arab forces were able to capture Carthage in 698 and Tangiers by 708. After the fall of Tangiers, many Berbers joined the Muslim army. In 740 Umayyad rule in the region was shaken by a major Berber revolt, which also involved Berber Kharijite Muslims. After a series of defeats, the caliphate was finally able to crush the rebellion in 742, although local Berber dynasties continued to drift away from imperial control from that time on.

Conquest of Hispania and Septimania: 711–721

The Muslim conquest of Iberia is notable for the brevity and unreliability of the available sources. After the Visigothic king of Spain Wittiza died in 710, the kingdom experienced a period of political division. Taking advantage of the situation, the Muslim Berber commander Tariq ibn Ziyad, who was stationed in Tangiers at the time, crossed the straits with an army of Arabs and Berbers. After defeating the forces of king Roderic, Muslim forces advanced capturing cities of the Gothic kingdom one after another. Some of them surrendered with agreements to pay tribute and local aristocracy retained a measure of former influence. By 713 Iberia was almost entirely under Muslim control. The events of the subsequent ten years, whose details are obscure, included capture of Barcelona and Narbonne, and a raid against Toulouse, followed by an expedition into Burgundy in 725. The last large-scale raid to the north ended with a Muslim defeat at the Battle of Tours at the hands of the Franks in 732.

Conquest of Transoxiana: 673–751

Transoxiana is the region northeast of Iran beyond the Amu Darya or Oxus river roughly corresponding with modern-day Uzbekistan, Tajikistan, and parts of Kazakhstan. Initial incursions across the Oxus river were aimed at Bukhara (673) and Samarqand (675) and their results were limited to promises of tribute payments. Further advances were hindered for a quarter century by political upheavals of the Umayyad caliphate. This was followed by a decade of rapid military progress under the leadership of the new governor of Khurasan, Qutayba ibn Muslim, which included conquest of Bukhara and Samarqand in 706–712. The expansion lost its momentum when Qutayba was killed during an army mutiny and the Arabs were placed on the defensive by an alliance of Sogdian and Türgesh forces with support from Tang China. However, reinforcements from Syria helped turn the tide and most of the lost lands were reconquered by 741. Muslim rule over Transoxania was consolidated a decade later when a Chinese-led army was defeated at the Battle of Talas (751).

Other campaigns and end of early conquests

In 646 a Byzantine naval expedition was able to briefly recapture Alexandria. The same year Mu‘awiya, the governor of Syria and future founder of the Umayyad dynasty, ordered construction of a fleet. Three years later it was put to use in a pillaging raid of Cyprus, soon followed by a second raid in 650 that concluded with a treaty under which Cypriots surrendered many of their riches and slaves. In 688 the island was made into a joint dominion of the caliphate and the Byzantine Empire under a pact which was to last for almost 300 years.

In 639–640 Arab forces began to make incursions into Armenia, which had been partitioned into a Byzantine province and a Sasanian province. There is considerable disagreement among ancient and modern historians about events of the following years, and nominal control of the region may have passed several times between Arabs and Byzantines. Although Muslim dominion was finally established by the time the Umayyads acceded to power in 661, it was not able to implant itself solidly in the country, and Armenia experienced a national and literary efflorescence over the next century. As with Armenia, Arab advances into other lands of the Caucasus region, including Georgia, had as their end assurances of tribute payment and these principalities retained a large degree of autonomy. This period also saw a series of clashes with the Khazar kingdom whose center of power was in the lower Volga steppes, and which vied with the caliphate over control of the Caucasus.

Other Muslim military ventures met with outright failure. Despite a naval victory over the Byzantines in 654 at the Battle of the Masts, the subsequent attempt to besiege Constantinople was frustrated by a storm which damaged the Arab fleet. Later sieges of Constantinople in 668–669 (674–78 according to other estimates) and 717–718 were thwarted with the help of the recently invented Greek fire. In the east, although Arabs were able to establish control over most Sasanian-controlled areas of modern Afghanistan after the fall of Persia, the Kabul region resisted repeated attempts of invasion and would continue to do so until it was conquered by the Saffarids three centuries later.

By the time of the Abbasid revolution in the middle of the 8th century, Muslim armies had come against a combination of natural barriers and powerful states that impeded further military progress. The wars produced diminishing returns in personal gains and fighters increasingly left the army for civilian occupations. The priorities of the rulers have also shifted from conquest of new lands to administration of the acquired empire. Although the Abbasid era witnessed some new territorial gains, such as the conquest of Sicily and the conquest of Crete, the period of rapid centralized expansion would now give way to an era when further Spread of Islam would be slow and accomplished through the efforts of local dynasties, missionaries, and traders.

Socio-political developments

The military victories of armies from the Arabian Peninsula heralded the expansion of the Arabs' culture and religion. The conquests were followed by a large-scale migration of families and whole tribes from Arabia into the lands of the Middle East. The conquering Arabs had already possessed a complex and sophisticated society. Emigrants from Yemen brought with them agricultural, urban, and monarchical traditions; members of the Ghassanid and Lakhmid tribal confederations had experience of collaboration with the empires. The rank and file of the armies was drawn from both nomadic and sedentary tribes, while the leadership came mainly from the merchant class of the Hejaz.

Two fundamental policies were implemented during the reign of the second caliph Umar (634–44): the bedouins would not be allowed to damage agricultural production of the conquered lands and the leadership would cooperate with the local elites. To that end, the Arab-Muslim armies were settled in segregated quarters or new garrison towns such as Basra, Kufa and Fustat. The latter two became the new administrative centers of Iraq and Egypt, respectively. Soldiers were paid a stipend and prohibited from seizing lands. Arab governors supervised collection and distribution of taxes, but otherwise left the old religious and social order intact. At first, many provinces retained a large degree of autonomy under the terms of agreements made with Arab commanders. As the time passed, the conquerors sought to increase their control over local affairs and make existing administrative machinery work for the new regime. This involved several types of reorganization. In the Mediterranean region, city-states which traditionally governed themselves and their surrounding areas were replaced by a territorial bureaucracy separating town and rural administration. In Egypt, fiscally independent estates and municipalities were abolished in favor of a simplified administrative system. In the early eighth century, Syrian Arabs began to replace Coptic functionaries and communal levies gave way to individual taxation. In Iran, the administrative reorganization and construction of protective walls prompted agglomeration of quarters and villages into large cities such as Isfahan, Qazvin, and Qum. Local notables of Iran, who at first had almost complete autonomy, were incorporated into the central bureaucracy by the ʿAbbasid period. The similarity of Egyptian and Khurasanian official paperwork at the time of the caliph al-Mansur (754–75) suggests a highly centralized empire-wide administration.

The society of new Arab settlements gradually became stratified into classes based on wealth and power. It was also reorganized into new communal units that preserved clan and tribal names but were in fact only loosely based around old kinship bonds. Arab settlers turned to civilian occupations and in eastern regions established themselves as a landed aristocracy. At the same time, distinctions between the conquerors and local populations began to blur. In Iran, the Arabs largely assimilated into local culture, adopting the Persian language, customs and marrying Persian women. In Iraq, non-Arab settlers flocked to garrison towns. Soldiers and administrators of the old regime came to seek their fortunes with the new masters, while slaves, laborers and peasants fled there seeking to escape the harsh conditions of life in the countryside. Non-Arab converts to Islam were absorbed into the Arab-Muslim society through an adaptation of the tribal Arabian institution of clientage, in which protection of the powerful was exchanged for loyalty of the subordinates. The clients (mawali) and their heirs were regarded as virtual members of the clan. The clans became increasingly economically and socially stratified. For example, while the noble clans of the Tamim tribe acquired Persian cavalry units as their mawali, other clans of the same tribe had slave laborers as theirs. Slaves often became mawali of their former masters when they were freed.

Contrary to belief of earlier historians, there is no evidence of mass conversions to Islam in the immediate aftermath of the conquests. The first groups to convert were Christian Arab tribes, although some of them retained their religion into the Abbasid era even while serving as troops of the caliphate. They were followed by former elites of the Sasanian empire, whose conversion ratified their old privileges. With time, the weakening of non-Muslim elites facilitated the breakdown of old communal ties and reinforced the incentives of conversion which promised economic advantages and social mobility. By the beginning of the eighth century, conversions became a policy issue for the caliphate. They were favored by religious activists, and many Arabs accepted equality of Arabs and non-Arabs. However, conversion was associated with economic and political advantages, and Muslim elites were reluctant to see their privileges being diluted. Public policy towards converts varied depending on the region and was changed by successive Umayyad caliphs. These circumstances provoked opposition from non-Arab converts, whose ranks included many active soldiers, and helped set the stage for the civil war which ended with the fall of the Umayyad dynasty.

Conversions and tax reform

The Arab-Muslim conquests followed a general pattern of nomadic conquests of settled regions, whereby conquering peoples became the new military elite and reached a compromise with the old elites by allowing them to retain local political, religious, and financial authority. Peasants, workers, and merchants paid taxes, while members of the old and new elites collected them. Payment of taxes, which for peasants often reached half of the value of their produce, was not only an economic burden, but also a mark of social inferiority. Scholars differ in their assessment of relative tax burdens before and after the conquests. John Esposito states that in effect this meant lower taxes. According to Bernard Lewis, available evidence suggests that the change from Byzantine to Arab rule was "welcomed by many among the subject peoples, who found the new yoke far lighter than the old, both in taxation and in other matters". In contrast, Norman Stillman writes that although the tax burden of the Jews under early Islamic rule was comparable to that under previous rulers, Christians of the Byzantine Empire (though not Christians of the Persian empire, whose status was similar to that of the Jews) and Zoroastrians of Iran shouldered a considerably heavier burden in the immediate aftermath of the conquests.

In the wake of the early conquests taxes could be levied on individuals, on the land, or as collective tribute. During the first century of Islamic expansion, the words jizya and kharaj were used in all three senses, with context distinguishing between individual and land taxes. Regional variations in taxation at first reflected the diversity of previous systems. The Sasanian Empire had a general tax on land and a poll tax having several rates based on wealth, with an exemption for aristocracy. This poll tax was adapted by Arab rulers, so that the aristocracy exemption was assumed by the new Arab-Muslim elite and shared by local aristocracy who converted to Islam. The nature of Byzantine taxation remains partly unclear, but it appears to have been levied as a collective tribute on population centers and this practice was generally followed under the Arab rule in former Byzantine provinces. Collection of taxes was delegated to autonomous local communities on the condition that the burden be divided among its members in the most equitable manner. In most of Iran and Central Asia local rulers paid a fixed tribute and maintained their autonomy in tax collection.

Difficulties in tax collection soon appeared. Egyptian Copts, who had been skilled in tax evasion since Roman times, were able to avoid paying the taxes by entering monasteries, which were initially exempt from taxation, or simply by leaving the district where they were registered. This prompted imposition of taxes on monks and introduction of movement controls. In Iraq, many peasants who had fallen behind with their tax payments, converted to Islam and abandoned their land for Arab garrison towns in hope of escaping taxation. Faced with a decline in agriculture and a treasury shortfall, the governor of Iraq al-Hajjaj forced peasant converts to return to their lands and subjected them to the taxes again, effectively forbidding them to convert to Islam. In Khorasan, a similar phenomenon forced the native aristocracy to compensate for the shortfall in tax collection out of their own pockets, and they responded by persecuting peasant converts and imposing heavier taxes on poor Muslims.

The situation where conversion to Islam was penalized in an Islamic state could not last, and the devout Umayyad caliph Umar II (717–720) has been credited with changing the taxation system. Modern historians doubt this account, although details of the transition to the system of taxation elaborated by Abbasid-era jurists are still unclear. Umar II ordered governors to cease collection of taxes from Muslim converts, but his successors obstructed this policy and some governors sought to stem the tide of conversions by introducing additional requirements such as circumcision and the ability to recite passages from the Quran. Taxation-related grievances of non-Arab Muslims contributed to the opposition movements which resulted in the Abbasid revolution. Under the new system that was eventually established, kharaj came to be regarded as a tax levied on the land, regardless of the taxpayer's religion. The poll-tax was no longer levied on Muslims, but the treasury did not necessarily suffer and converts did not gain as a result, since they had to pay zakat, which was probably instituted as a compulsory tax on Muslims around 730. The terminology became specialized during the Abbasid era, so that kharaj no longer meant anything more than land tax, while the term jizya was restricted to the poll-tax on dhimmis.

The influence of jizya on conversion has been a subject of scholarly debate. Julius Wellhausen held that the poll tax amounted to so little that exemption from it did not constitute sufficient economic motive for conversion. Similarly, Thomas Arnold states that jizya was "too moderate" to constitute a burden, "seeing that it released them from the compulsory military service that was incumbent on their Muslim fellow subjects." He further adds that converts escaping taxation would have to pay the legal alms, zakat, that is annually levied on most kinds of movable and immovable property. Other early 20th century scholars suggested that non-Muslims converted to Islam en masse in order to escape the poll tax, but this theory has been challenged by more recent research. Daniel Dennett has shown that other factors, such as desire to retain social status, had greater influence on this choice in the early Islamic period.

Policy toward non-Muslims

The Arab conquerors did not repeat the mistake made by the Byzantine and Sasanian empires, who had tried and failed to impose an official religion on subject populations, which had caused resentments that made the Muslim conquests more acceptable to them. Instead, the rulers of the new empire generally respected the traditional middle-Eastern pattern of religious pluralism, which was not one of equality but rather of dominance by one group over the others. After the end of military operations, which involved sacking of some monasteries and confiscation of Zoroastrian fire temples in Syria and Iraq, the early caliphate was characterized by religious tolerance and peoples of all ethnicities and religions blended in public life. Before Muslims were ready to build mosques in Syria, they accepted Christian churches as holy places and shared them with local Christians. In Iraq and Egypt, Muslim authorities cooperated with Christian religious leaders. Numerous churches were repaired and new ones built during the Umayyad era.

The first Umayyad caliph Muawiyah sought to reassure the conquered peoples that he was not hostile to their religions and made an effort to enlist support from Christian Arab elites. There is no evidence for public display of Islam by the state before the reign of Abd al-Malik (685–705), when Quranic verses and references to Muhammad suddenly became prominent on coins and official documents. This change was motivated by a desire to unify the Muslim community after the second civil war and rally them against their chief common enemy, the Byzantine empire.

A further change of policy occurred during the reign of Umar II (717–720). The disastrous failure of the siege of Constantinople in 718 which was accompanied by massive Arab casualties led to a spike of popular animosity among Muslims toward Byzantium and Christians in general. At the same time, many Arab soldiers left the army for civilian occupations and they wished to emphasize their high social status among the conquered peoples. These events prompted introduction of restrictions on non-Muslims, which, according to Hoyland, were modeled both on Byzantine curbs on Jews, starting with the Theodosian Code and later codes, which contained prohibitions against building new synagogues and giving testimony against Christians, and on Sassanid regulations that prescribed distinctive attire for different social classes.

In the following decades Islamic jurists elaborated a legal framework in which other religions would have a protected but subordinate status. Islamic law followed the Byzantine precedent of classifying subjects of the state according to their religion, in contrast to the Sasanian model which put more weight on social than on religious distinctions. In theory, like the Byzantine empire, the caliphate placed severe restrictions on paganism, but in practice most non-Abrahamic communities of the former Sasanian territories were classified as possessors of a scripture (ahl al-kitab) and granted protected (dhimmi) status.

Mark R. Cohen writes that the jizya paid by Jews under Islamic rule provided a "surer guarantee of protection from non-Jewish hostility" than that possessed by Jews in the Latin West, where Jews "paid numerous and often unreasonably high and arbitrary taxes" in return for official protection, and where treatment of Jews was governed by charters which new rulers could alter at will upon accession or refuse to renew altogether. The Pact of Umar, which stipulated that Muslims must "do battle to guard" the dhimmis and "put no burden on them greater than they can bear", was not always upheld, but it remained "a steadfast cornerstone of Islamic policy" into early modern times.