Umayyad Caliphate

Umayyad Caliphate

اَلْخِلافَةُ ٱلأُمَوِيَّة
The Umayyad Caliphate at its greatest extent in AD 750
The Umayyad Caliphate at its greatest extent in AD 750
Capital-in-exileCórdoba (756–1031)
Common languagesClassical Arabic (official) – Coptic, Greek, Latin, Persian (official in certain regions until the reign of Abd al-Malik) – Aramaic, Armenian, Berber languages, African Romance, Mozarabic, Sindhi, Georgian, Prakrit
Sunni Islam
• 661–680
Muawiya I (first)
• 744-750
Marwan II (last)
• Muawiya I becomes Caliph
estimated from 660 to 665
• Defeat and death of Marwan II by the Abbasids
72011,100,000[1] km2 (4,300,000 sq mi)
• 724
CurrencyGold dinar and dirham
Preceded by
Succeeded by
Rashidun Caliphate
Byzantine Empire
Visigothic Kingdom
Exarchate of Africa
Kingdom of the Aurès
Kingdom of Altava
Brahman dynasty of Sindh
Hephthalite Empire
Abbasid Caliphate
Emirate of Córdoba
Kingdom of Nekor
Emirate of Tlemcen
Amir al-Mu'minin (أمير المؤمنين), Caliph (خليفة)

The Umayyad Caliphate (661–750 CE; UK: ˈ-/,[3] US: d/;[4][5][6] Arabic: اَلْخِلافَةُ ٱلأُمَوِيَّة‎, romanizedal-Khilāfatu l-ʾUmawiyyah)[7] was the second of the four major caliphates established after the death of Muhammad. The caliphate was ruled by the Umayyad dynasty (Arabic: اَلأُمَوِيُّون‎, al-ʾUmawiyyūn, or بَنُو أُمَيَّة, Banū ʾUmayya, "Sons of Umayya"), hailing from Mecca. The third Caliph, Uthman ibn Affan (r. 644–656), was a member of the Umayyad clan. The family established dynastic, hereditary rule with Muawiya ibn Abi Sufyan, long-time governor of Syria, who became the sixth Caliph after the end of the First Muslim Civil War in 661. After Mu'awiyah's death in 680, conflicts over the succession resulted in a Second Civil War[8] and power eventually fell into the hands of Marwan I from another branch of the clan. Syria remained the Umayyads' main power base thereafter, and Damascus was their capital.

The Umayyads continued the Muslim conquests, incorporating the Transoxiana, Sindh, the Maghreb and the Iberian Peninsula (Al-Andalus) into the Muslim world. At its greatest extent, the Umayyad Caliphate covered 11,100,000 km2 (4,300,000 sq mi)[1] and 33 million people,[2] making it one of the largest empires in history in both area and proportion of the world's population. The dynasty was eventually overthrown by a rebellion led by the Abbasids in 750. Survivors of the dynasty established themselves in Cordoba in the form of an Emirate and then a Caliphate, lasting until 1031.

The Umayyad caliphate ruled over a vast multiethnic and multicultural population. Christians, who still constituted a majority of the Caliphate's population, and Jews were allowed to practice their own religion but had to pay a head tax (the jizya) from which Muslims were exempt.[9] There was, however, the Muslim-only zakat tax, which was earmarked explicitly for various welfare progammes.[9][10] Prominent positions were held by Christians, some of whom belonged to families that had served in Byzantine governments. The employment of Christians was part of a broader policy of religious accommodation that was necessitated by the presence of large Christian populations in the conquered provinces, as in Syria. This policy also boosted Muawiya's popularity and solidified Syria as his power base.[11][12]



Early influence

In the decades preceding the advent of Islam in the early 7th century, the Umayyads or "Banu Umayya" were a leading clan of the Quraysh in Mecca.[13] By the end of the 6th century, the Umayyads dominated the Quraysh's increasingly prosperous trade networks with Syria in the north and Yemen in the south.[14] In the process, they developed economic and military alliances with the nomadic Arab tribes that controlled the northern and central Arabian desert expanses that their caravans traversed, allowing them a degree of political power in the region.[14] The Umayyads under the leadership of Abu Sufyan ibn Harb were the principal leaders of Meccan opposition to the Islamic prophet Muhammad, but after the latter captured Mecca in 630, Abu Sufyan and the Quraysh embraced Islam.[15][16] To reconcile his influential Qurayshi tribesmen, Muhammad gave his former opponents, including Abu Sufyan, a stake in the new order.[17][18][19] Abu Sufyan and the Umayyads relocated to Medina, Islam's political center, to maintain their new-found political influence in the nascent Muslim community.[20]

Following Muhammad's death in 632, a succession crisis ensued and nomadic tribes throughout Arabia that had embraced Islam defected from the Medina-based Muslim state.[21] Abu Bakr, trusted by the Ansar and the Muhajirun (Muhammad's earliest supporters from Medina and Mecca, respectively) as one of Muhammad's closest friends and accepted by the late converts from the Quraysh as a native Meccan who assured their influential role in state matters, was chosen as caliph (political and religious leader of the Muslim community).[22] Abu Bakr showed favor to the Umayyads by awarding them command roles in the Muslim conquest of Syria. One of the appointees was Yazid, the son of Abu Sufyan who owned property and maintained trade networks in Syria.[23][24]

Abu Bakr's successor, Caliph Umar (r. 634–644), though he actively curtailed the influence of the Qurayshi elite in favor of Muhammad's earlier supporters in the administration and military, did not disturb the growing foothold of Abu Sufyan's sons in Syria, which was all but conquered by 638.[25] When his overall commander over the province, Abu Ubayda ibn al-Jarrah, died in 639, he appointed Yazid governor of its Damascus, Palestine and Jordan districts.[25] Yazid died shortly after and Umar installed his brother Mu'awiya in his place.[26] Umar's exceptional treatment of Abu Sufyan's sons may have stemmed from his respect for the family, their burgeoning alliance with the powerful Banu Kalb tribe as a counterbalance to the influence of the Himyarite tribes in the Homs district or the lack of a suitable candidate at the time, particularly amid the plague of Amwas which had already killed Abu Ubayda and Yazid.[26] Under Mu'awiya's stewardship, Syria remained domestically peaceful, organized and well-defended from its former Byzantine rulers.[27]

Caliphate of Uthman

Umar's successor, Uthman ibn Affan, was a wealthy Umayyad and early Muslim convert with marital ties to Muhammad.[28] He was elected by the shura council, composed of Muhammad's cousin Ali, al-Zubayr ibn al-Awwam, Talha ibn Ubayd Allah, Sa'd ibn Abi Waqqas and Abd al-Rahman ibn Awf, all of whom were close, early companions of Muhammad and belonged to the Quraysh.[28][29] He was chosen over Ali because he would ensure the concentration of state power into the hands of the Quraysh, as opposed to Ali's determination to diffuse power among all of the Muslim factions.[30] From early in his reign, he displayed explicit favoritism to his kinsmen, in stark contrast to his predecessors.[28][29] He appointed his family members as governors over the regions successively conquered under Umar and himself, namely much of the Sasanian Empire, i.e. Iraq and Iran, and the former Byzantine territories of Syria and Egypt.[29] In Medina, he relied extensively on the counsel of his Umayyad cousins, the brothers al-Harith and Marwan ibn al-Hakam.[31] According to the historian Wilferd Madelung, this policy stemmed from Uthman's "conviction that the house of Umayya, as the core clan of Quraysh, was uniquely qualified to rule in the name of Islam".[28]

Uthman's nepotism gained him the ire of the Ansar and the members of the shura.[28][29] In 645/46, he added the Jazira (Upper Mesopotamia) to Mu'awiya's Syrian governorship and granted the latter's request to take possession of all Byzantine crown lands in Syria to help pay his troops.[32] He forwarded the surplus taxes from the wealthy provinces of Kufa and Egypt to the treasury in Medina, which he used at his personal disposal, frequently disbursing its funds and war booty to his Umayyad relatives.[33] Moreover, the lucrative Sasanian crown lands of Iraq, which Umar had designated as communal property for the benefit of the Arab garrison towns of Kufa and Basra, were turned into caliphal crown lands to be used at Uthman's discretion.[34] Mounting resentment against Uthman's rule in Iraq and Egypt and among the Ansar and Quraysh of Medina culminated in the siege and killing of the caliph in 656. In the assessment of the historian Hugh N. Kennedy, Uthman was killed because of his determination to centralize control over the Caliphate's government by the traditional elite of the Quraysh, particularly his Umayyad clan, which he believed possessed the "experience and ability" to govern, at the expense of the interests, rights and privileges of many early Muslims.[31]

First Fitna

In the aftermath of Uthman's assassination, Ali was recognized as caliph in Medina, though his support stemmed from the Ansar and the Iraqis, while the bulk of the Quraysh were wary of his rule.[31][35] Indeed, the first challenge to his authority came from the Qurayshi leaders al-Zubayr and Talha, who, though opposed to Uthman's empowerment of the Umayyad clan, feared that their own influence and the power of the Quraysh in general would dissipate under Ali.[36][37] Backed by one of Muhammad's wives, A'isha, they attempted to rally support against Ali among the troops of Basra, prompting the caliph to leave for Iraq's other garrison town, Kufa, where he could better confront his challengers.[38] Ali defeated them at the Battle of the Camel, in which al-Zubayr and Talha were slain and A'isha consequently entered self-imposed seclusion.[38][39] Ali's sovereignty was thereafter recognized in Basra and Egypt and he established Kufa as the Caliphate's new capital.[39]

Though Ali was able to replace Uthman's governors in Egypt and Iraq with relative ease, Mu'awiya had developed a solid power-base and an effective military against the Byzantines from the Arab tribes of Syria, which he governed since Umar's reign.[38] Mu'awiya did not claim the caliphate, but was determined to retain control of Syria and opposed Ali in the name of avenging his kinsman Uthman, accusing the caliph of culpability in his death.[40][41][42] Following his victory in Basra, Ali marched against Mu'awiya, the two sides meeting at the Euphrates river boundary separating their territories. The two sides fought to a stalemate in the ensuing Battle of Siffin in early 657, and Ali was compelled to settle the matter with Mu'awiya by arbitration, though the talks failed to achieve a resolution.[43]

The decision to arbitrate fundamentally weakened Ali's political position as he was forced to negotiate with Mu'awiya on equal terms, while it drove a significant number of his most pious supporters, who became known as the Kharijites, to revolt.[44] Ali's coalition steadily disintegrated and many Iraqi tribal nobles secretly defected to Mu'awiya, while the latter's ally Amr ibn al-As ousted Ali's governor from Egypt in July 658, dealing a blow to the caliph's influence.[43][45] In July 660, Mu'awiya was formally recognized as caliph in Jerusalem by his Syrian tribal allies.[43] Ali's attempt to once again march against Mu'awiya was aborted as a result of Ali's assassination by a Kharijite in January 661.[46] His son al-Hasan succeeded him, but abdicated in return for compensation upon Mu'awiya's arrival to Iraq with his Syrian army in the summer.[43] At that point, Mu'awiya entered Kufa and received the allegiance of the Iraqis.[47]


Old map of western Eurasia and northern Africa showing the expansion of the Caliphate from Arabia to cover most of the Middle East, with the Byzantine Empire outlined in green
The expansion of the Muslim Caliphate until 750, from William R. Shepherd's Historical Atlas.
  Muslim state at the death of Muhammad   Expansion under the Rashidun Caliphate   Expansion under the Umayyad Caliphate
Umayyad Caliphate coin imitating the coinage of Sasanid Empire ruler Khosrau II. Coin of the time of Mu'awiya I ibn Abi Sufyan (Muawiyah I). BCRA (Basra) mint; "Ubayd Allah ibn Ziyad, governor". Dated AH 56 = AD 675/6. Sasanian style bust imitating Khosrau II right; bismillah and three pellets in margin; c/m: winged creature right / Fire altar with ribbons and attendants; star and crescent flanking flames; date to left, mint name to right.

Muawiyah's personal dynasty, the "Sufyanids" (descendants of Abu Sufyan), reigned from 661 to 684, until his grandson Muawiya II. The reign of Muawiyah I was marked by internal security and external expansion. On the internal front, only one major rebellion is recorded, that of Hujr ibn Adi in Kufa. Hujr ibn Adi supported the claims of the descendants of Ali to the caliphate, but his movement was easily suppressed by the governor of Iraq, Ziyad ibn Abi Sufyan. Hujr, who had been a sahabah (companion of Muhammad), was sentenced to death by Muawiya for his support of Ali.[48]

Muawiyah also encouraged peaceful coexistence with the Christian communities of Syria, granting his reign with "peace and prosperity for Christians and Arabs alike",[49] and one of his closest advisers was Sarjun ibn Mansur, the father of John of Damascus. At the same time, he waged unceasing war against the Byzantine Roman Empire. During his reign, Rhodes and Crete were occupied, and several assaults were launched against Constantinople. After their failure, and faced with a large-scale Christian uprising in the form of the Mardaites, Muawiyah concluded a peace with Byzantium. Muawiyah also oversaw military expansion in North Africa (the foundation of Kairouan) and in Central Asia (the conquest of Kabul, Bukhara, and Samarkand).

Muawiyah was succeeded by his son, Yazid I, in 680. This hereditary accession was opposed by a number of prominent Muslims, most notably Abd-Allah ibn al-Zubayr, son of a companion of Muhammad, and Husayn ibn Ali, the younger son of Ali. The resulting conflict is known as the Second Fitna.[8] Ibn al-Zubayr had fled Medina for Mecca, where he remained in opposition until his death. The people of Kufa invited Husayn to their city and revolt against the Umayyads. However, Yazid I prevented this alliance by having Kufa occupied[50] and Husayn and his family intercepted on their way to Kufa in the Battle of Karbala, in which Husayn and his male family members were killed.[50] Word of Husayn's death fueled further opposition movements, one centered in Medina and the other around Kharijites in Basra. In 683, Yazid's army suppressed the Medinese opposition at the Battle of al-Harrah and then besieged Mecca. During the campaign, widespread pillaging and the damaging of both the Grand Mosque in Medina and the Kaaba in Mecca caused deep resentment and became a major cause for censure of the Umayyads in later histories of the period.

Yazid died while the siege was still in progress, and the Umayyad army returned to Damascus, leaving Ibn al-Zubayr in control of Mecca. Yazid's son, Muawiya II (683–684), initially succeeded him but seems to have never been recognized as caliph outside of Syria. Two factions developed within Syria: the Confederation of Qays, who supported Ibn al-Zubayr, and the Quda'a, who supported Marwan, a descendant of Umayya via Wa'il ibn Umayyah. The partisans of Marwan triumphed at a battle at Marj Rahit, near Damascus, in 684, and Marwan became Caliph shortly thereafter.

First Marwanids

The Dome of the Rock in Jerusalem

Marwan's first task was to assert his authority against the rival claims of Ibn al-Zubayr, who was at this time recognized as caliph throughout most of the Islamic world. Marwan recaptured Egypt for the Umayyads, but died in 685, having reigned for only nine months.

Marwan was succeeded by his son, Abd al-Malik (685–705), who reconsolidated Umayyad control of the caliphate. The early reign of Abd al-Malik was marked by the revolt of Al-Mukhtar, which was based in Kufa. Al-Mukhtar hoped to elevate Muhammad ibn al-Hanafiyyah, another son of Ali, to the caliphate, although Ibn al-Hanafiyyah himself may have had no connection to the revolt. The troops of al-Mukhtar engaged in battles both with the Umayyads in 686, defeating them at the river Khazir near Mosul, and with Ibn al-Zubayr in 687, at which time the revolt of al-Mukhtar was crushed. In 691, Umayyad troops reconquered Iraq, and in 692 the same army captured Mecca. Ibn al-Zubayr was killed in the attack.

The second major event of the early reign of Abd al-Malik was the construction of the Dome of the Rock in Jerusalem. Although the chronology remains somewhat uncertain, the building seems to have been completed in 692, which means that it was under construction during the conflict with Ibn al-Zubayr. This had led some historians, both medieval and modern, to suggest that the Dome of the Rock was built as a destination for pilgrimage to rival the Kaaba, which was under the control of Ibn al-Zubayr.

Abd al-Malik is credited with centralizing the administration of the Caliphate and with establishing Arabic as its official language. He also introduced a uniquely Muslim coinage, marked by its aniconic decoration, which supplanted the Byzantine and Sasanian coins that had previously been in use. Abd al-Malik also recommenced offensive warfare against Byzantium, defeating the Byzantines at Sebastopolis and recovering control over Armenia and Caucasian Iberia.

Following Abd al-Malik's death, his son, Al-Walid I (705–715), became caliph. Al-Walid was also active as a builder, sponsoring the construction of Al-Masjid al-Nabawi in Medina and the Great Mosque of Damascus.

In the year 712, Muhammad bin Qasim, an Umayyad general, sailed from the Persian Gulf into Sindh and conquered both the Sindh and the Punjab regions along the Indus river. The conquest of Sindh and Punjab, in modern-day Pakistan, although costly, were major gains for the Umayyad Caliphate. However, further gains were halted by the death of Al-Hajjaj bin Yusuf Al-Thaqafi, as after his death Muhammad was called back from his conquests. After this, Muslim chroniclers admit that the Caliph Mahdi "gave up the project of conquering any part of India".[citation needed]

A major figure during the reigns of both al-Walid and Abd al-Malik was the Umayyad governor of Iraq, Al-Hajjaj bin Yousef. Many Iraqis remained resistant to Umayyad rule, and to maintain order al-Hajjaj imported Syrian troops, which he housed in a new garrison town, Wasit. These troops became crucial in the suppression of a revolt led by an Iraqi general, Ibn al-Ash'ath, in the early eighth century.

Two coins of the Umayyad Caliphate, based on Byzantine prototypes. Copper falus, Aleppo, Syria, circa 695

Al-Walid was succeeded by his brother, Sulayman (715–717), whose reign was dominated by a protracted siege of Constantinople. The failure of the siege marked the end of serious Arab ambitions against the Byzantine capital. However, the first two decades of the eighth century witnessed the continuing expansion of the Caliphate, which pushed into the Iberian Peninsula in the west, and into Transoxiana in the Muslim conquest of Transoxiana (under Qutayba ibn Muslim) and northern India in the east.

Arab sources claim Qutayba ibn Muslim briefly took Kashgar from China and withdrew after an agreement[51] but modern historians entirely dismiss this claim.[52][53][54]

In AD 715, the Umayyad Caliphate deposed the ikhshid of the Principality of Farghana, and installed a new king Alutar on the throne. The deposed king fled to Kucha (seat of Anxi Protectorate), and sought Chinese intervention. The Tang dynasty sent 10,000 troops under Zhang Xiaosong to Ferghana. He defeated Alutar and the Arab occupation force at Namangan and reinstalled the ikhshid on the throne.[55]

The Chinese defeated the Umayyad invaders at the Battle of Aksu (717), forcing the Umayyad commander, Al-Yashkuri, and his army to flee to Tashkent.[56][57]

Sulayman was succeeded by his cousin, Umar ibn Abd al-Aziz (717–720), whose position among the Umayyad caliphs is somewhat unusual. He is the only Umayyad ruler to have been recognized by subsequent Islamic tradition as a genuine caliph (khalifa) and not merely as a worldly king (malik).

Umar is honored for his attempt to resolve the fiscal problems attendant upon conversion to Islam. During the Umayyad period, the majority of people living within the caliphate were not Muslim, but Christian, Jewish, Zoroastrian, or members of other small groups. These religious communities were not forced to convert to Islam, but were subject to a tax (jizyah) which was not imposed upon Muslims. This situation may actually have made widespread conversion to Islam undesirable from the point of view of state revenue, and there are reports that provincial governors actively discouraged such conversions. It is not clear how Umar attempted to resolve this situation, but the sources portray him as having insisted on like treatment of Arab and non-Arab (mawali) Muslims, and on the removal of obstacles to the conversion of non-Arabs to Islam.

After the death of Umar, another son of Abd al-Malik, Yazid II (720–724) became caliph. Yazid is best known for his "iconoclastic edict", which ordered the destruction of Christian images within the territory of the Caliphate. In 720, another major revolt arose in Iraq, this time led by Yazid ibn al-Muhallab.

Hisham and the limits of military expansion

The North gate of the city of Resafa, site of Hisham's palace and court

The final son of Abd al-Malik to become caliph was Hisham (724–43), whose long and eventful reign was above all marked by the curtailment of military expansion. Hisham established his court at Resafa in northern Syria, which was closer to the Byzantine border than Damascus, and resumed hostilities against the Byzantines, which had lapsed following the failure of the last siege of Constantinople. The new campaigns resulted in a number of successful raids into Anatolia, but also in a major defeat (the Battle of Akroinon), and did not lead to any significant territorial expansion.

From the caliphate's north-western African bases, a series of raids on coastal areas of the Visigothic Kingdom paved the way to the permanent occupation of most of Iberia by the Umayyads (starting in 711), and on into south-eastern Gaul (last stronghold at Narbonne in 759). Hisham's reign witnessed the end of expansion in the west, following the defeat of the Arab army by the Franks at the Battle of Tours in 732. In 739 a major Berber Revolt broke out in North Africa, which was probably the largest military setback in the reign of Caliph Hisham. From it, emerged some of the first Muslim states outside the Caliphate. It is also regarded as the beginning of Moroccan independence, as Morocco would never again come under the rule of an eastern Caliph or any other foreign power until the 20th century. It was followed by the collapse of Umayyad authority in al-Andalus. In India the Arab armies were defeated by the south Indian Chalukya dynasty and by the north Indian Pratiharas Dynasty in the 8th century and the Arabs were driven out of India.[58][59][60]

In the Caucasus, the confrontation with the Khazars peaked under Hisham: the Arabs established Derbent as a major military base and launched several invasions of the northern Caucasus, but failed to subdue the nomadic Khazars. The conflict was arduous and bloody, and the Arab army even suffered a major defeat at the Battle of Marj Ardabil in 730. Marwan ibn Muhammad, the future Marwan II, finally ended the war in 737 with a massive invasion that is reported to have reached as far as the Volga, but the Khazars remained unsubdued.

The Umayyad Caliphate at its greatest extent in AD 750

Hisham suffered still worse defeats in the east, where his armies attempted to subdue both Tokharistan, with its center at Balkh, and Transoxiana, with its center at Samarkand. Both areas had already been partially conquered, but remained difficult to govern. Once again, a particular difficulty concerned the question of the conversion of non-Arabs, especially the Sogdians of Transoxiana. Following the Umayyad defeat in the "Day of Thirst" in 724, Ashras ibn 'Abd Allah al-Sulami, governor of Khurasan, promised tax relief to those Sogdians who converted to Islam, but went back on his offer when it proved too popular and threatened to reduce tax revenues.

Discontent among the Khurasani Arabs rose sharply after the losses suffered in the Battle of the Defile in 731. In 734, al-Harith ibn Surayj led a revolt that received broad backing from Arabs and natives alike, capturing Balkh but failing to take Merv. After this defeat, al-Harith's movement seems to have been dissolved. The problem of the rights of non-Arab Muslims would continue to plague the Umayyads.

Third Fitna

Hisham was succeeded by Al-Walid II (743–44), the son of Yazid II. Al-Walid is reported to have been more interested in earthly pleasures than in religion, a reputation that may be confirmed by the decoration of the so-called "desert palaces" (including Qusayr Amra and Khirbat al-Mafjar) that have been attributed to him. He quickly attracted the enmity of many, both by executing a number of those who had opposed his accession, and by persecuting the Qadariyya.

In 744, Yazid III, a son of al-Walid I, was proclaimed caliph in Damascus, and his army tracked down and killed al-Walid II. Yazid III has received a certain reputation for piety, and may have been sympathetic to the Qadariyya. He died a mere six months into his reign.

Yazid had appointed his brother, Ibrahim, as his successor, but Marwan II (744–50), the grandson of Marwan I, led an army from the northern frontier and entered Damascus in December 744, where he was proclaimed caliph. Marwan immediately moved the capital north to Harran, in present-day Turkey. A rebellion soon broke out in Syria, perhaps due to resentment over the relocation of the capital, and in 746 Marwan razed the walls of Homs and Damascus in retaliation.

Marwan also faced significant opposition from Kharijites in Iraq and Iran, who put forth first Dahhak ibn Qays and then Abu Dulaf as rival caliphs. In 747, Marwan managed to reestablish control of Iraq, but by this time a more serious threat had arisen in Khorasan.

Abbasid Revolution

The Caliphate at the beginning of the Abbasid revolt, before the Battle of the Zab

The Hashimiyya movement (a sub-sect of the Kaysanites Shia), led by the Abbasid family, overthrew the Umayyad caliphate. The Abbasids were members of the Hashim clan, rivals of the Umayyads, but the word "Hashimiyya" seems to refer specifically to Abu Hashim, a grandson of Ali and son of Muhammad ibn al-Hanafiyya. According to certain traditions, Abu Hashim died in 717 in Humeima in the house of Muhammad ibn Ali, the head of the Abbasid family, and before dying named Muhammad ibn Ali as his successor. This tradition allowed the Abbasids to rally the supporters of the failed revolt of Mukhtar, who had represented themselves as the supporters of Muhammad ibn al-Hanafiyya.

Beginning around 719, Hashimiyya missions began to seek adherents in Khurasan. Their campaign was framed as one of proselytism (dawah). They sought support for a "member of the family" of Muhammad, without making explicit mention of the Abbasids. These missions met with success both among Arabs and non-Arabs (mawali), although the latter may have played a particularly important role in the growth of the movement.

Around 746, Abu Muslim assumed leadership of the Hashimiyya in Khurasan. In 747, he successfully initiated an open revolt against Umayyad rule, which was carried out under the sign of the black flag. He soon established control of Khurasan, expelling its Umayyad governor, Nasr ibn Sayyar, and dispatched an army westwards. Kufa fell to the Hashimiyya in 749, the last Umayyad stronghold in Iraq, Wasit, was placed under siege, and in November of the same year Abul Abbas as-Saffah was recognized as the new caliph in the mosque at Kufa.[citation needed] At this point Marwan mobilized his troops from Harran and advanced toward Iraq. In January 750 the two forces met in the Battle of the Zab, and the Umayyads were defeated. Damascus fell to the Abbasids in April, and in August, Marwan was killed in Egypt.

The victors desecrated the tombs of the Umayyads in Syria, sparing only that of Umar II, and most of the remaining members of the Umayyad family were tracked down and killed. When Abbasids declared amnesty for members of the Umayyad family, eighty gathered to receive pardons, and all were massacred. One grandson of Hisham, Abd al-Rahman I, survived, escaped across North Africa, and established an emirate in Moorish Iberia (Al-Andalus). In a claim unrecognized outside of al-Andalus, he maintained that the Umayyad Caliphate, the true, authentic caliphate, more legitimate than the Abbasids, was continued through him in Córdoba. It was to survive for centuries.

Previté-Orton argues that the reason for the decline of the Umayyads was the rapid expansion of Islam. During the Umayyad period, mass conversions brought Persians, Berbers, Copts, and Aramaics to Islam. These mawalis (clients) were often better educated and more civilised than their Arab overlords. The new converts, on the basis of equality of all Muslims, transformed the political landscape. Previté-Orton also argues that the feud between Syria and Iraq further weakened the empire.[61]