The Abbasid Dynasty, known to its supporters as the ‘blessed dynasty’, which imposed its authority on the Islamic empire in 132/750, claimed to inaugurate a new era of justice, piety and happiness. The dynasty ruled the Islamic Caliphate from 750 to 1258 AD, making it one of the longest and most influential Islamic dynasties. For most of its early history, it was the largest empire in the world, and this meant that it had contact with distant neighbors such as the Chinese and Indians in the East, and the Byzantines in the West, allowing it to adopt and synthesize ideas from these cultures.
The replacement of the Umayyads by the Abbasids in the leadership of the Islamic community was more than a mere change of dynasty. It was a revolution in the history of Islam, as important a turning point as the French and Russian Revolutions in the history of the west. The Umayyad administration (661-750) of the Islamic Empire created serious grievances among various political, religious, social and ethnic groups. Their monopoly of power denied other people important administrative positions and the accompanying privileges and benefits. The Umayyads favored Syrian Arabs over other Muslims and treated mawali, newly converted Muslims, as second class citizens. The most numerous group of mawali were the Persians, who lived side by side with Arabs in the east who were angry at the favor shown to Syrian Arabs. Together, they were ripe for rebellion. Other Muslims were angry with the Umayyads for turning the caliphate into a hereditary dynasty, for their over-dependence upon the bureaucracy of the preceding Byzantine Empire, for levying taxes forbidden by the Qur’an, and for their ethnocentric policies. Some believed that a single family should not hold power, while Shiites believed that true authority belonged to the family of the Prophet Muhammad through his son-in-law Ali, and the Umayyads were not part of Muhammad’s family.
The Umayyads were accused