The Abbasid revolution (Arabic: اَلثَّوْرَة اَلْعَبَّاسِيَّةِ, romanized: aṯ-Ṯawra al-ʿAbbāsiyyah), was the overthrow of the Umayyad Caliphate (661–750), the second major caliphate, by the Hashimiyya movement, resulting in the establishment of the Abbasid Caliphate (750–1517), the third major caliphate.
The Abbasid revolution originated in the eastern province of Khorasan in the mid-8th century, fuelled by widespread discontent with Umayyad rule. The revolt was led by the Abbasid dynasty, descendants of al-ʿAbbas ibn ʿAbd al-Muṭṭalib, an uncle of the Islamic prophet Muhammad from the Banu Hashim. Although Abu Muslim, who directed the uprising in Khurāsān, played a decisive organizational and military role, his precise ethnic origins remain debated in the sources.
The revolutionary forces (ahl Khurāsān) were heavily composed of long-settled Arab tribal groups in Khurāsān (Khorasani Arabs), many of whom were affiliated with South Arabian (Yamani) confederations that had been established there since the early Islamic conquests. They formed the backbone and majority of the forces and brought the Abbasids to power. Non-Arab Muslim converts (the mawālī), including Iranian Muslims, and local supporters participated too in the movement.
Background
By the 740s CE, the Umayyad Caliphate found itself in critical condition. A succession crisis in 744 led to the Third Fitna, which raged across the Middle East for three years. The very next year, al-Dahhak ibn Qays al-Shaybani initiated a Kharijite rebellion that would continue until 746. Concurrent with this, a rebellion broke out in reaction to Marwan II's decision to move the capital from Damascus to Harran, resulting in the destruction of Homs – also in 746. It was not until 747 that Marwan II was able to pacify the provinces; the Abbasid revolution began within the course of months.
Nasr ibn Sayyar was appointed governor of Khorasan by Hisham ibn Abd al-Malik in 738. He held on to his post throughout the war of succession, being confirmed as governor by Marwan II in the aftermath.
Khorasan's expansive size and low population density meant that the Arab denizens – both military and civilian – lived largely outside of the garrisons built during the spread of Islam into Persia (then under the influence of Zoroastrianism). This was in contrast to the rest of the Umayyad provinces, where Arabs tended to seclude themselves in fortresses to avoid interacting with the locals. Arab settlers in Khorasan left their traditional lifestyle and settled among the native Iranian peoples. While intermarriage with non-Arabs elsewhere in the Empire was discouraged or even banned, it slowly became a habit within eastern Khorasan; and the Arabs began adopting Persian dress and as the two languages influenced one another, the ethnic barriers gradually eroded.
Causes
Support for the Abbasid revolution came from people of diverse backgrounds, with almost all levels of society supporting armed opposition to Umayyad rule. This was especially pronounced among Muslims of non-Arab descent, though even Arab Muslims resented Umayyad rule and centralized authority over their nomadic lifestyles. Both Sunnis and Shi'as supported efforts to overthrow the Umayyads, as did non-Muslim subjects of the empire who resented religious discrimination.
Discontent among Shi'as
The Battle of Karbala, where Husayn ibn Ali, the grandson of Muhammad, alongside his kin and companions, were massacred by Umayyad forces in 680 CE, became a rallying cry of opposition against the Umayyads. The Abbasids used the memory of Karbala extensively to gain popular support against the Umayyads, which further rallied Shi'ite support. In the decades preceding the Abbasid revolution, several Shi'ite and Alid uprisings had taken place against the Umayyads. To an extent, rebellion against the Umayyads bore an early association with Shi'ite ideas. This included the Tawwabin uprising led by Sulayman ibn Surad in 684–685 and Mukhtar al-Thaqafi's uprising in 685–687. Later on, the revolts of Zayd ibn Ali in 740 and the uprising of Abd Allah ibn Mu'awiya in 747–748, who even established temporary rule over much of Iran, paved the way for the Abbasid revolution.
The Hashimiyya movement (a sub-sect of the Shi'ite Kaysanites) was largely responsible for starting the final efforts against the Umayyad dynasty, initially with the goal of replacing the Umayyads with an Alid ruling family. Initially, the Abbasid family kept quiet about their identity, simply stating that they wanted a ruler from the descendant of Muhammad upon whose choice as caliph the Muslim community would agree to. Many Shi'ites naturally assumed that this meant an Alid ruler, a belief which the Abbasids tacitly encouraged to gain Shi'ite support. The Abbasids claimed that Abu Hashim, the grandson of Ali through his son Muhammad ibn al-Hanafiyya, had formally transferred the Imamate to Muhammad ibn Ali ibn Abdallah in 717, and thus the Imamate was transferred to the house of al-Abbas.
Although the anecdote is considered a fabrication, at the time it allowed the Abbasids to rally the supporters of the failed revolt of Mukhtar al-Thaqafi, who had represented themselves as the supporters of Muhammad ibn al-Hanafiyya. By the time the revolution was in full swing, most Kaysanite Shia had either transferred their allegiance to the Abbasid dynasty (in the case of the Hashimiyya), or differed to other branches of Shi'ism, and so the Kaysanites ceased to exist.
Discontent among non-Arab Muslims
The Umayyad state is remembered as an Arab-centric state, being run by and for the benefit of those who were ethnically Arab though Muslim in creed. The non-Arab Muslims resented their marginal social position and were easily drawn into Abbasid opposition to Umayyad rule. Arabs dominated the bureaucracy and military, and were housed in fortresses separate from the local population outside of Arabia. Even after converting to Islam, non-Arabs or Mawali could not live in these garrison cities. The non-Arabs were not allowed to work for the government nor could they hold officer positions in the Umayyad military and they still had to pay the jizya tax for non-Muslims. Non-Muslims under Umayyad rule were subject to these same injunctions. Racial intermarriage between Arabs and non-Arabs was rare. When it did occur, it was only allowed between an Arab man and a non-Arab woman while non-Arab men were generally not free to marry Arab women.
Conversion to Islam occurred gradually. If a non-Arab wished to convert to Islam, they not only had to give up their own names but also had to remain a second-class citizen. The non-Arab would be "adopted" by an Arab tribe, though they would not actually adopt the tribe's name as that would risk pollution of perceived Arab racial purity. Rather, the non-Arab would take the last name of "freedman of al-(tribe's name)", even if they were not a slave prior to conversion. This essentially meant they were subservient to the tribe who sponsored their conversion.
Although converts to Islam made up roughly 10% of the native population – most of the people living under Umayyad rule were not Muslim – this percent was significant due to the very small number of Arabs. Gradually, the non-Arab Muslims outnumbered the Arab Muslims, causing alarm among the Arab nobility. Socially, this posed a problem as the Umayyads viewed Islam as the property of the aristocratic Arab families. There was a rather large financial problem posed to the Umayyad system as well. If the new converts to Islam from non-Arab peoples stopped paying the jizya tax stipulated by the Qur'an for non-Muslims, the empire would go bankrupt. This lack of civil and political rights eventually led the non-Arab Muslims to support the Abbasids, despite the latter also being Arab.
Even as the Arab governors adopted the more sophisticated Iranian methods of governmental administration, non-Arabs were still prevented from holding such positions. Non-Arabs were not even allowed to wear Arabian style clothing, so strong were the feelings of Arab racial superiority cultivated by the Umayyads. Much of the discontent this caused led to the Shu'ubiyya movement, an assertion of non-Arab racial and cultural equality with Arabs. The movement gained support among Egyptians, Arameans and Berbers, though this movement was most pronounced among Iranian peoples. The early Muslim conquest of Persia was coupled with an anti-Iranian Arabization policy which led to much discontent.
The Umayyad governor of Iraq and the east, Al-Hajjaj ibn Yusuf, forced all the mawali who had left for cities, in order to avoid paying the kharaj tax, to return to their lands. He was upset at the usage of Persian as the court language in the eastern Islamic empire, and ordered it to be changed to Arabic. Up until the reign of Caliph Abd al-Malik ibn Marwan, the Roman coinage was used throughout of Syria, Egypt and Arabia while Sassanian coins were through Iraq and Iraq, the caliph introduced the first official Islamic coinage in Arabic. He also transformed the government accounts of Damascus from Greek to Arabic and the government accounts of Kufa were transformed from Persian to Arabic.
Discontent among non-Muslims
Support for the Abbasid revolution was an early example of people of different faiths aligning with a common cause. This was due in large part to policies of the Umayyads which were regarded as particularly oppressive to anyone following a faith other than Islam. In 741, the Umayyads decreed that non-Muslims could not serve in government posts. The Abbasids were aware of this discontent, and made efforts to balance both its Muslim character as well as its partially non-Muslim constituency.
The non-Muslim aristocracy around Merv supported the Abbasids, and thus retained their status as a privileged governing class regardless of religious belief.
Historical events
Buildup
Beginning around 719, Hashimiyya missions began to seek adherents in Khurasan. Their campaign was framed as one of proselytism. They sought support for "a member of the House of Muhammad who shall be pleasing to everyone", without making explicit mention of the Abbasids. These missions met with success both among Arabs and non-Arabs, although the latter may have played a particularly important role in the growth of the movement. A number of Shi'ite rebellions – by Kaysanites, Hashimiyya and mainstream Shi'ites – took place in the final years of Umayyad rule, just around the same time that tempers were flaring among the Syrian contingents of the Umayyad army regarding alliances and wrongdoings during the Third Fitna.
At this time Kufa was the center for the opposition to Umayyad rule, particularly Ali's supporters and Shias. In 741–42 Abu Muslim made his first contact with Abbasid agents there, and eventually he was introduced to the head of Abbasids, Ibrahim al-Imam, in Mecca. Around 746, Abu Muslim assumed leadership of the Hashimiyya in Khurasan. Unlike the Alid revolts which were open and straightforward about their demands, the Abbasids along with the Hashimite allies slowly built up an underground resistance movement to Umayyad rule. Secret networks were used to build a power base of support in the eastern Muslim lands to ensure the revolution's success. This buildup not only took place right on the heels of the Zaydi Revolt in Iraq, but also concurrently with the Berber Revolt in Iberia and Maghreb, the Ibadi revolt in Yemen and Hejaz, and the Third Fitna in the Levant, with the revolt of al-Harith ibn Surayj in Khorasan and Central Asia occurring concurrently with the revolution itself. The Abbasids spent their preparation time watching as the Umayyad Empire was besieged from within itself in all four cardinal directions, and G. R. Hawting has asserted that even if the Umayyad rulers had been aware of the Abbasids' preparations, it would not have been possible to mobilize against them.
Revolt of Ibn Surayj
In 746, Ibn Surayj began his revolt at Merv without success at first, even losing his secretary Jahm bin Safwan. After joining forces with other rebel factions, Ibn Surayj drove the Umayyad governor Nasr ibn Sayyar and his forces to Nishapur. The two factions crossed each other shortly thereafter, with Ibn Surayj's faction being crushed. Western Khorasan was controlled by Abd Allah ibn Mu'awiya at the time, cutting Ibn Sayyar in the east off from Marwan II. In the summer of 747, Ibn Sayyar sued for peace, which was accepted by the remaining rebels. The rebel leader was assassinated by a son of Ibn Surayj in a revenge attack while at the same time, another Shi'ite revolt had begun in the villages. The son of the remaining rebels signed the peace accord and Ibn Sayyar returned to his post in Merv in August of 747 – just after Abu Muslim initiated a revolt of his own.