The Umayyad dynasty ruled for many years. In the later years, due to infighting and turmoil, the reign of the Muslim empire was taken over by the Abbasids who overthrew the Umayyad dynasty in 750 CE. The Abbasid family of caliphs was related to Abbas ibn Abd al-Muttalib who was Prophet Muhammad"s uncle. The direct relation with the Prophet led the Abbasids to believe that they had more right over the caliphate than any other family. During the last years of the Umayyad rule, Abbasids started criticizing the Umayyad administration and more importantly the Umayyad rulers" moral character, and started to rebel against the Umayyad rule. In 750 CE, the Abbasids overthrew the Umayyad regime and killed a number of them on grounds of corruption.
After taking over the rule, the Abbasids moved their capital from Damascus to Baghdad. The era of the Abbasid Caliphs (which was the third caliphate after the Rashidun and Umayyad caliphate) in the middle of 8th century, is known as the Islamic Golden Age. Abbasid"s stayed in power in varying capacities (political and sometimes religious) for more than seven centuries until their role ended with the transfer of power in 1519 CE. Their rule was briefly disrupted when Halagu Khan attacked Baghdad in 1258 CE. During the Abbasid"s time, Baghdad became the new centre of learning and culture for the whole world. The Abbasids established a House of Wisdom in Baghdad where they employed non-Muslim and Muslim scholars to gather knowledge from all around the world and translated it into Arabic. Baghdad became the unrivalled champion in philosophy, science, education and medicine. Knowledge was gained and centralized about ancient civilizations like Chinese, Roman, Indian, Egyptian, Greek, Byzantine and North African thus opening channels for people of diverse backgrounds who started coming to Baghdad to seek knowledge of various disciplines.
The holy shrines and sanctuaries of Jerusalem were renovated time and again by the Abbasid Caliphs of Baghdad. Other port cities under the Islamic rule like Acre, Arsuf, Jaffa, Haifa, Caesarea and Ashkelon received money from the state"s treasury and were also made stronger by fortifying them.
Every year merchants from different cities would come to Jerusalem to take part in various trade fairs. Jerusalem became a major trading hub for goods such as spices, olive oils, soaps, glassware, silks and various European products. Christians continued to actively make pilgrimage to Jerusalem and Christian holy places in Jerusalem continued to get generous donations made by European Christian pilgrims. It was also during the Abbasid caliphate (specifically during Harun Rashid"s time) that the first contact with the Frankish Kingdom of Charlemagne took place. This contact held great importance because it resulted in the construction of many churches in Jerusalem from the money sent by Charlemagne.
Although the Abbasids were less frequent visitors of Jerusalem than the Ummayads, they still carried on the modernization and construction in Jerusalem. For example, in 758 CE, Al-Mansur ordered the Dome of the Rock to be renovated which had collapsed as a result of an earthquake.
The Abbasids however didn"t tend to other affairs of Palestine as much as the Umayyads. One of the reasons was that the Abbasids had moved their caliphate from Damascus (closer to Jerusalem) to Baghdad. In those areas various Arab tribes had formed local federations. Disputes amongst those tribes led to many battles between these Arab tribes in the period 793 "" 796 CE during which many were killed. The ongoing civil war thus resulted in a major destruction of Palestinian areas.
During the reign of the Abbasids, the Muslim world saw the height of its power and glory. However, around 842 CE during the caliphate of al-Wathiq, the power of the caliphate started to decline. The region around Iraq fell to the Buyid Dynasty, by 945 CE. Although the Abbasids remained caliphs, their role was diminished to being only ceremonial in nature.
Other dynasties also ruled other parts of the Muslims world during these periods. The Zengid (or Zangid) dynasty was one that ruled parts of Syria and northern Iraq on behalf of the Seljuk Empire. The Seljuq Empire controlled a vast area that stretched from the Hindu Kush to eastern Anatolia and also included regions in Central Asia and the Persian Gulf. They ruled those areas from 1037 CE to 1194 CE. The Ayyubid dynasty on the other hand was a Sunni Muslim dynasty of Kurdish origin centered in Cairo and Damascus that ruled much of the Middle East during the 12th and 13th centuries CE. The Ayyubid dynasty (to which Salah-ud-Din, son of Ayyub, belonged) ruled parts of the Muslim world from 1171 CE to 1341 CE.