Abbasid Caliphate
The Abbasid Caliphate or Abbasid Empire was the third Islamic caliphate, ruled by the Abbasid dynasty. The dynasty was descended from Muhammad's uncle, Abbas ibn Abd al-Muttalib, after whom it is named. The Abbasids rose to power in 750, when the Abbasid Revolution overthrew the preceding Umayyad Caliphate, and they ruled as caliphs from their metropole in Iraq until 1258, with Baghdad as their capital for most of their history.
The Abbasid Revolution had its origins and first successes in the easterly region of Khurasan, far from the Levantine center of Umayyad influence. The Abbasids first centered their government in Kufa, Iraq, but in 762 the second caliph al-Mansur founded the city of Baghdad and made it the capital. Baghdad became a center of science, culture, arts, and invention, ushering in what became known as the Golden Age of Islam. It hosted several key academic institutions, such as the House of Wisdom, as well as a multi-ethnic and multi-religious population, which made the city famous as a centre of learning across the world. The Abbasid period was marked by the use of bureaucrats in government, including the vizier, as well as a growing inclusion of non-Arab Muslims in the ummah and among the political elites.
The height of Abbasid power and prestige is traditionally associated with the reign of Harun al-Rashid. After his death, a civil war brought new divisions and was followed by significant changes to the character of the state, including the creation of a new professional army recruited mainly from Turkic slaves and the construction of a new capital, Samarra, in 836. The 9th century also saw many provinces becoming increasingly autonomous, giving rise to local dynasties that controlled different regions of the empire, such as the Aghlabids, Tahirids, Samanids, Saffarids, and Tulunids. After a period of turmoil in the 860s, the caliphate regained some stability and its seat returned to Baghdad in 892.
During the 10th century, the caliphs were reduced to mere figureheads, with real political and military power resting in the hands of the Iranian Buyids and the Seljuq Turks, who took control of Baghdad in 945 and 1055, respectively. The Abbasids eventually regained control of Iraq during the reign of Caliph al-Muqtafi and extended their rule into Iran during the reign of Caliph al-Nasir. This revival ended in 1258 with the sack of Baghdad by the Mongols under Hulagu Khan and the execution of Caliph al-Musta'sim, which marked the effective end of the Abbasid Caliphate. A surviving branch of the Abbasid dynasty was formally reinstated in 1261 by the Mamluk sultans in Cairo, but it lacked any political power. The dynasty continued to claim symbolic authority until the Ottoman conquest of Egypt in 1517, the last Abbasid caliph being al-Mutawakkil III.
History
Abbasid Revolution (747–750)
The Abbasid caliphs descended from Abbas ibn Abd al-Muttalib, one of the youngest uncles of Muhammad and of the same Banu Hashim clan. This family relation to Muhammad made them appealing to those who were discontented with the rule of the Umayyad caliphs, who did not descend from the same family. Over the course of their rule, the Umayyads even suppressed several rebellions that attempted to bring other members of Muhammad's family to power. One of the claims that the Abbasids made in the early years of their political movement was that Abu Hashim, the son of Muhammad ibn al-Hanafiyya and grandson of Ali, had formally transferred the Imamate to Muhammad ibn Ali and thus to the Abbasid family. Muhammad ibn Ali began to campaign in Persia for the return of power to the family of Muhammad, the Hashemites, during the reign of Umar II. Later, after they had attained power and needed to broaden their support among Muslims, the Abbasids supplemented this claim with other claims to justify their legitimacy.The Abbasids also distinguished themselves from the Umayyads by attacking their moral character and administration in general. According to Ira Lapidus, "The Abbasid revolt was supported largely by Arabs, mainly the aggrieved settlers of Merv with the addition of the Yemeni faction and their Mawali". The Abbasids also appealed to non-Arab Muslims, known as mawali, who remained outside the kinship-based society of the Arabs and were perceived as a lower class within the Umayyad empire.
During the reign of Marwan II, this opposition culminated in the rebellion of Ibrahim al-Imam, the fourth in descent from Abbas. Supported by the province of Khurasan, even though the governor opposed them, and the Shi'i Arabs, he achieved considerable success, but was captured in the year 747 and died, possibly assassinated, in prison.
On 9 June 747, Abu Muslim, rising from Khurasan, successfully initiated an open revolt against Umayyad rule, which was carried out under the sign of the Black Standard. Close to 10,000 soldiers were under Abu Muslim's command when the hostilities officially began in Merv. General Qahtaba followed the fleeing governor Nasr ibn Sayyar west defeating the Umayyads at the Battle of Gorgan, the Battle of Nahavand and finally in the Battle of Karbala, all in the year 748.
Ibrahim was captured by Marwan and was killed. The quarrel was taken up by Ibrahim's brother Abdallah, known by the name of Abu al-'Abbas as-Saffah, who defeated the Umayyads in 750 in the battle near the Great Zab and was subsequently proclaimed caliph. After this loss, Marwan fled to Egypt, where he was subsequently killed. The remainder of his family, barring one male, were also eliminated.
Establishment and consolidation (750–775)
Immediately after their victory, al-Saffah sent his forces to Central Asia, where his forces fought against Tang expansion during the Battle of Talas. Al-Saffah focused on putting down numerous rebellions in Syria and Iraq. The Byzantines conducted raids during these early distractions.One of the first major changes effected by Abbasid rule was the move of the caliphate's center of power from Syria to Iraq. This was closer to the Persian mawali support base of the Abbasids and the move addressed their demand for reduced Arab dominance in the empire. However, no definitive capital was yet selected. In these early Abbasid years, Kufa generally served as the administrative capital, but the caliphs were wary of the Alid sympathies in the city and did not always reside here. In 752, al-Saffah built a new city called al-Hashimiyya, at an uncertain location, most likely near Kufa. Later that same year, he moved to Anbar, where he built a new settlement for his Khurasani soldiers and a palace for himself.
File:Abbāsid Caliph al-Manṣūr from the genealogy, Cream of Histories.jpg|thumb|Portrait of al-Mansur from an Ottoman-era work, the "Cream of Histories" in 1598
It was al-Saffah's successor, Abu Ja'far al-Mansur who firmly consolidated Abbasid rule and faced down internal challenges. His uncle, Abdallah ibn Ali, the victor over the Umayyads at the Battle of the Zab, was the most serious potential rival for leadership and al-Mansur sent Abu Muslim, the Khurasani revolutionary commander, against him in 754. After Abu Muslim successfully defeated him, al-Mansur then turned to eliminate Abu Muslim himself. He arranged to have him arrested and executed in 755.
On the western frontier, the Abbasids were unable to re-assert caliphal control over the western and central Maghreb, which the Umayyads had lost in the 740s. One member of the Umayyad dynasty, Abd ar-Rahman, also managed to escape the purge of his family and established independent rule in al-Andalus in 756, founding the Umayyad Emirate of Córdoba.
In 756, al-Mansur had also sent over 4,000 Arab mercenaries to assist the Chinese Tang dynasty in the An Lushan Rebellion against An Lushan. The Abbasids, or "Black Flags" as they were commonly called, were known in Tang dynasty chronicles as the hēiyī Dàshí, "The Black-robed Tazi" . Later, Caliph Harun al-Rashid sent embassies to the Chinese Tang dynasty and established good relations with them. After the war, these embassies remained in China with al-Rashid establishing an alliance with China. Several embassies from the Abbasid Caliphs to the Chinese court have been recorded in the Old Book of Tang, the most important being those of al-Saffah, al-Mansur, and Harun al-Rashid.
File:Baghdad 150 to 300 AH.png|thumb|upright=1.2|Plan of Baghdad between 767 and 912 CE, according to William Muir
In 762, al-Mansur suppressed a rebellion in the Hejaz led by al-Nafs al-Zakiyya, a descendant from Ali ibn Abi Talib, whose challenge to the Abbasid claim to leadership was based on his Alid lineage and thus presented a serious political threat. He was defeated by an Abbasid army led by Isa ibn Musa. It was after this victory, in 762, that al-Mansur finally established a proper Abbasid capital, Baghdad – officially called Madinat al-Salam – located on the Tigris River, near the former ancient capital city of Ctesiphon. Prior to this, he had continued to consider multiple sites for a capital, including al-Hashimiyya, which he used as a capital for a while, and al-Rumiyya, which he used for a few months. Various other sites in the region also appear to have served as "capitals" under either al-Saffah or al-Mansur prior to the founding of Baghdad.
Al-Mansur centralised the judicial administration and, later, Harun al-Rashid established the institution of Great Qadi to oversee it. The Umayyad empire was mostly Arab; however, the Abbasids progressively became made up of more and more converted Muslims in which the Arabs were only one of many ethnicities. The Abbasids had depended heavily on the support of Persians in their overthrow of the Umayyads. Al-Mansur welcomed non-Arab Muslims to his court. While this helped integrate Arab and Persian cultures, it alienated many of their Arab supporters, particularly the Khurasani Arabs who had supported them in their battles against the Umayyads.