Reasons for the Fall of the Abbasid Caliphate

Abbasid Caliphate was the third Muslim Caliphate after the Rashidun and Umayyad caliphates. It was also the second Muslim dynasty after Umayyad Dynasty, as the rulers during this dynasty belonged only to the Abbasid family. 

The Abbasids took the throne in 750 AD after the fall of the Umayyad Dynasty. They ruled almost the entire Muslim world (directly or indirectly) for more than 500 years till 1258 AD. In 1258, Mongols occupied Baghdad and assassinated the last Abbasid caliph Mustasim, thus effectively bringing the downfall of the Abbasid Caliphate.

Though Abbasids remained caliphs for over 500 years, the gradual decline of their empire started almost from the beginning. The following are the top reasons behind the fall of the Abbasid Caliphate.

Fall of the Abbasid Caliphate - Main Reasons

Differences with Shia

Abbasids and Shia were together during the Hashemite movement, which overthrew the Umayyad Caliphate. But differences between the two parties started a few years after the emergence of the Abbasid Caliphate. Shia were expecting to become rulers after the fall of the Umayyads, but instead, the Abbasids took the throne, which resulted in another Sunni-Shia conflict. It prompted the Shiites to organize several rebellions (notably Alid revolts of 762-763 and 786) against the Abbasids, which weakened their rule. 

Fatimid (Ismaili Shia) captured North Africa and Hejaz, and the Buyid Dynasty controlled areas of Persia, Iraq, and Oman in the 10^th Century. On the other hand, Shiite terror organizations of Qaramites and Assassins (led by Hasan bin Sabah) also created problems in various parts of the Islamic world. Shia also supported Hulagu Khan during his successful invasion of Baghdad. All these revolts and conspiracies weakened the Caliphate miserably.

Civil Wars

Two civil wars during the 9^th Century plagued the Abbasid Caliphate. The first Abbasid civil war (811-819), known as the Fourth Fitna or Fourth Muslim Civil War, was fought between two brothers, Amin and Mamun. The Abbasid Caliphate achieved its zenith during the era of Harun al-Rashid, but this civil war between his two sons declined its power. Mamun remained victorious, but the civil war loosened the grip of his rule in several areas. A prominent one was the rise of the Tahirid dynasty in Khurasan. This autonomous dynasty is famous for being the first independent Iranian dynasty after the Sassanid Empire.

The second Abbasid civil war (known as the Fifth Fitna) was fought in 865-866 during the period known as Anarchy at Samarra (861-870). During this unrest, four caliphs succeeded each other in a short time. Both these civil wars declined the authority of the Caliphate miserably. Consequently, the tendency for rebellions and autonomous dynasties increased, risking political and economic stability.

Rebellions of the 9^th Century

The internal instability caused by civil wars resulted in the emergence of two major rebellions. The largest one was the rebellion by the Kharijites, an anarchist group. This rebellion continued for 30 years (866-896) in almost the entire area now comprising modern Iraq. Moreover, the Zanj Rebellion (869-883) also devastated a large part of the Caliphate and initiated the decline of the Abbasid Caliphate.

Autonomous Dynasties

The Umayyads strictly kept the central rule in the whole Caliphate. But different areas started to disintegrate during Abbasid Caliphate. As a result, several autonomous and semi-autonomous dynasties appeared in the areas away from the center during Abbasid Caliphate. 

The first such autonomous state was the Emirate of Cordoba, where the Umayyads became sovereign rulers in 756 AD. Later, several other rulers in different parts of the Caliphate parted ways from the Abbasids, and several dynasties formed in the later centuries. 

Though most of these dynasties accepted the suzerainty of the Abbasids, they remained independent in their affairs. Losing central control over large areas of the empire proved to be a significant reason for the decline and fall of the Abbasid Caliphate.

Role of Turkish Generals

People from Persia and Khurasan were the initial backers of the Abbasid Dynasty. But differences soon occurred between the ruling dynasty and their supporters due to religious and political differences. It forced the Abbasids to eliminate the influence of the Persians. In contrast to the Umayyad dynasty, Abbasids could not get much support from Arab tribes and had to trust the newly-converted Turks as their supporters.

Initially, Turkish forces assisted the Abbasids in regaining control of several areas (especially Iraq) from other dynasties. But later, the Turks became kingmakers who destabilized the Caliphate internally. They established their autonomous states in several parts of the Caliphate where the rule of the Abbasids was minimal. The rise of Turks on the political stage also proved to be a leading factor behind the fall of the Abbasid Caliphate.

Mongol Invasion

At the start of the 13^th Century, Mongol tribes united and rose under the leadership of Genghis Khan. Later, they started to invade and capture areas around Mongolia. Soon, they occupied China, Central Asia, and Eastern Europe. Mongols initiated their invasions against Abbasids in 1236, but most of their efforts failed against the strong military of the Caliphate.

The final invasion of Mongols started in 1257 when several Christian kingdoms were also assisting the Mongols. After capturing nearby areas from various factions, the Mongols reached Baghdad in 1258. The last Abbasid caliph was too afraid to fight against the invaders and surrendered to the Mongols after a successful siege. Later, Mongols assassinated caliph Mustasim and plundered and destroyed the capital Baghdad which marked the end of the Abbasid Caliphate.