22. The Abbasid Caliphate was one of the great dynasties of the Muslim Empire. For approximately how long did it reign?
From Quiz The Abbasid Dynasty
Answer:
500 years
The caliphate overthrew the Umayyad Dynasty in 750 CE and remained in power until Baghdad was destroyed in 1258.
The establishment of the original caliphate came into being when the Prophet Muhammad passed away in 632 CE. In the period to 661 CE there were four "rightly guided" caliphs, but the first three did not sit well with the Shia Muslims who wrote them off as usurpers, proclaiming Ali, Muhammad's son-in-law and cousin, as the only true caliph. Ali was murdered in 661 CE which opened the door to the absolute monarchy installed by the Umayyads.
To their credit, the Umayyads administered the realm successfully. Their biggest problem was that they ignored those they considered less worthy, applying politics or brute force to keep them in check. This alienated a number of Arab and non-Arab factions, the largest of these being the Shias and the Persians. The Abbasids, who were the descendants of Abbas ibn Abd al-Muttalib (an uncle of Muhammad), used this division to their advantage, and established a propaganda campaign that would be the fore-runner to their open revolution.