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 the Prophet 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
Second 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, Imam
Ibrahim, 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 rebellion in
Yemen and
Hijaz, and the
Third Fitna in the
Levant, with the revolt of
al-Harith ibn Surayj in
Khurasan 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
School of Oriental and African Studies Professor Emeritus 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 Umayyad governor Nasr ibn Sayyar and his forces to
Nishapur; the two factions double-crossed each other shortly thereafter, with Ibn Surayj's faction being crushed. Western Khorasan was controlled by
Abdallah 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.
Persian phase On 9 June 747 (Ramadan 25, 129AH), Abu Muslim successfully initiated an open revolt against Umayyad rule, which was carried out under the sign of the
Black Standard. Abu Muslim rose in the name of an
Imam, still unnamed at the time but spoken of as
al-Rida, rallying support from Khorasanians and Shi'ites. Close to 10,000 soldiers were under Abu Muslim's command when the hostilities officially began in
Merv. On 14 February 748 he established control of Merv, expelling
Nasr ibn Sayyar less than a year after the latter had put down Ibn Surayj's revolt, and dispatched an army westwards. Newly commissioned Abbasid officer
Qahtaba ibn Shabib al-Ta'i, along with his sons
Al-Hasan ibn Qahtaba and
Humayd ibn Qahtaba, pursued Ibn Sayyar to
Nishapur and then pushed him further west to
Qumis, in western Persia. That August, al-Ta'i defeated an Umayyad force of 10,000 at the
Battle of Jurjān (near modern
Gorgan), southeast of the Caspian Sea. Ibn Sayyar regrouped with reinforcements from the Caliph at
Rey near today's Capital "Tehran", only for that city to fall as well as the Caliph's commander; once again, Ibn Sayyar fled west and died on 9 December 748 while trying to reach
Hamedan in south Western Persia. Al-Ta'i rolled west through Khorasan, defeating a 50,000 strong Umayyad force at
Isfahan in Central Persia in March 749. At
Nahavand south western Persia, the Umayyads attempted to make their last stand in Persia. Umayyad forces fleeing Hamedan and the remainder of Ibn Sayyar's men joined with those already garrisoned. Qahtaba defeated an Umayyad relief contingent from Syria while his son al-Hasan laid siege to Nahavand for more than two months. The Umayyad military units from Syria within the garrison cut a deal with the Abbasids, saving their own lives by selling out the Umayyad units from Khorasan who were all put to death. After almost ninety years, Umayyad rule in Khorasan had finally come to an end. At the same time that al-Ta'i took Nishapur, located in North Eastern Khorasan, Abu Muslim was strengthening the Abbasid grip on the Muslim North East. Abbasid governors were appointed over
Transoxiana and
Bactria (overlapping contemporary Turkmenistan, Tajikistan, Uzbekistan, Kyrgyzstan and Kazakhstan), while the rebels who had signed a peace accord with Nasr ibn Sayyar were also offered a peace deal by Abu Muslim only to be double crossed and wiped out. With the pacification of any rebel elements in the east and the surrender of Nahavand in the west, the Abbasids were the undisputed rulers of Khorasan.
Mesopotamia phase depicting As-Saffah as he receives
pledges of allegiance in Kufa The Abbasids wasted no time in continuing from Persia into Mesopotamia. In August 749, Umayyad commander
Yazid ibn Umar al-Fazari attempted to meet the forces of al-Ta'i before they could reach
Kufa. Not to be outdone, the Abbasids launched a nighttime raid on al-Fazari's forces before they had a chance to prepare. During the raid, al-Ta'i himself was finally killed in battle. Despite the loss, al-Fazari was routed and fled with his forces to
Wasit. The
Siege of Wasit took place from that August until July 750. Although a respected military commander had been lost, a large portion of the Umayyad forces were essentially trapped inside Wasit and could be left in their virtual prison while more offensive military actions were made. Concurrently with the siege in 749, the Abbasids crossed the
Euphrates and took Kufa. The son of
Khalid al-Qasri – a disgraced Umayyad official who had been tortured to death a few years prior – began a pro-Abbasid riot starting at the city's citadel. On 2 September 749, al-Hasan bin Qahtaba essentially just walked right in to the city and set up shop. Some confusion followed when
Abu Salama, an Abbasid officer, pushed for an Alid leader. Abu Muslim's confidante Abu Jahm reported what was happening, and the Abbasids acted preemptively. On Friday, 28 November 749, before the siege of Wasit had even finished,
al-Saffah, the great-grandson of Muhammad's uncle,
al-Abbas, was recognized as the new caliph in the mosque at Kufa. Abu Salama, who witnessed twelve military commanders from the revolution pledging allegiance, was embarrassed into following suit. Just as quickly as Qahtaba's forces marched from Khorosan to Kufa, so did the forces of
Abdallah ibn Ali and
Abu Awn Abd al-Malik ibn Yazid march on
Mosul(in today's Northern Iraq). At this point Marwan II mobilized his troops from
Harran (Today's South Central Turkey) and advanced toward Mesopotamia. On 16 January 750 the two forces met on the left bank of a tributary of the Tigris in the
Battle of the Zab, and nine days later Marwan II was defeated and his army was completely destroyed. The battle is regarded as what finally sealed the fate of the Umayyads. All Marwan II could do was flee through Syria and into Egypt, with each Umayyad town surrendering to the Abbasids as they swept through in pursuit.
Damascus fell to the Abbasids in April, and in August
Marwan II and his family were tracked down by a small force led by Abu Awn and
Salih ibn Ali (the brother of Abdallah ibn Ali) and killed in Egypt. Al-Fazari, the Umayyad commander at Wasit, held out even after the defeat of Marwan II in January. The Abbasids promised him amnesty in July, but immediately after he exited the fortress they executed him instead. After almost exactly three years of rebellion, the Umayyad state came to an end.
Massacre of Umayyad remnants 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 under
Abd Allah ibn Ali declared amnesty for members of the Umayyad family, eighty gathered in
Jaffa to receive pardons and all were massacred. It was said that the massacre took place during a gathering banquet, with Abd Allah reportedly continuing to dine throughout the event. ʿAbd Allah ibn Ali presented the mass killings of Umayyads as retaliation for
Husayn's death at
Karbala. ==Tactics==