What caused the downfall of the Abbasids?

Answer 1

The Abbassid Caliphate contracted in two general phases. The first phase was from 750 CE to 850 CE which led to the loss of the distant provinces in Spain, Morocco, Algeria, and Tunisia. The second phase occurred from 1100-1258 CE which resulted in the capitulation of the entire state.

Abbassid Caliphate Contraction in the First Phase
The reasons that Abbassid territory diminished between 750 to 850 CE, fracturing into the Umayyads (Spain), Idrissids (Morocco), Aghlabids (Algeria, Tunisia, Sicily), and other smaller states.

1) Religious Issues: The Abbassids came to power with the help of the Shiites and Mawali (Non-Arab Moslems like Persians and Amazigh). Even though the Abbassids did increase the rights and station of Mawali, it was never practical nor desirable for the Abbassids to become Shiite. As a result, he alienated much of North Africa, which at this time had a large Shiite and Kharijite population. (The Kharijites would have been alienated anyway as they were a very religious minority.)

2) Distance: There were no effective routes of communication between the Western Edges of the Caliphate and Baghdad. This made local administrators more powerful as they would have to make their own decisions anyway (it would take too long for a messenger to go to Baghdad and return). Many figured that they might as well make the change more permanent.

3) Political Issues: This refers specifically to Umayyad Spain which was the only part of the Umayyad Caliphate that never became Abbassid when Abu Al-Abbas As-Saffah rose against the Umayyads. As a result of the uprising, Amir Abd El-Rahman fled to Spain and set it up as a Caliphate in opposition to the Abbassids.

The Fall of the Abbassid Caliphate
The reasons for the eventual fall of the Abbassid Caliphate which occurred in 1100-1258 CE are the following.

1) Corruption: The Abbassid Caliphate had become one of the richest and most prosperous states in the world at that time, changing its leadership from honest brokers of power (Amir al-Mu'aminin - Prince of the Believers used to actually mean something) to individuals more concerned with money. This created strong resentment from those who were outside of the Abbassid purview.

2) Mawali Inclusion: The Abbassids were an Arab Caliphate (as opposed to the Samanids who were a Persian Caliphate) and were expected by many Arabs to treat other Arabs better than the Mawali. However, the Abbassids consistently treated Persians equal to or better than their Arab brethren which created animosity and a sense of betrayal. Many Arabs saw the Persians as the major backers of the Caliphate and that they were a tool for Persian interests. It was also perceived that the Persians were first servants to the caliphs but climbed way up the social ladder to a place they did not belong.

3) Turkish Armies: Armies like the Mamluk (who were retained by the Abbassids for the defense of the Caliphate) were Turks who defended an Arab State. Beginning in this period, they began to realize that they had the capacity to create their own states considering how vast their powers were as a military. This idea also came to the fore for Turks outside of the Caliphate. As a result, there were Mamluk uprisings, Seljuq attacks, and other Turkish Armies turning against Baghdad.

4) Rise of the Mongols: Hülegü Khan put the final nail in the coffin by massacring Baghdad and a number of Persian cities when he conquered the territory for the Great Khanate.