The Abbasid Caliphate or, more simply, the Abbasids (Arabic: العبّاسيّون / ISO 233: al-‘abbāsīyūn), was the third of the Islamic caliphates. It was ruled by the Abbasid dynasty of caliphs, who built their capital in Baghdad after overthrowing the Umayyad caliphate from all but the al-Andalus region.
The cAbbasid realm witnessed a brief revival under caliphs al-Nasir (r. 1180–1225) and al-Mustansir (r. 1226–42), when Baghdad once again became the greatest center for the arts of the book in the Islamic world and the Mustansiriyya Madrasa (1228–33), the first college for the four canonical schools of Sunni law, was built. However, this burst of artistic vitality came to a temporary halt with the sack of Baghdad by the Ilkhanid branch of the Mongols in 1258
In the early period of 'Abbasid rule, al-Mansur, the second caliph of the dynasty, continued the reorganization of the administration of the empire along the lines that had been laid down by his Umayyad predecessor, 'Abd al-Malik. Much of the 'Abbasid administration, for example, was left in the hands of well-educated Persian civil servants, many of whom came from families that had traditionally served the Sassanid kings.
The Abbasids established the position of vizier in their administration, which was the equivalent of a "vice-caliph," or second-in-command. Eventually, this change meant that many caliphs under the Abbasids ended up in a much more ceremonial role than ever before, with the vizier in real power. A new Persian bureaucracy began to replace the old Arab aristocracy, and the entire administration reflected these changes, demonstrating that the new dynasty was different in many ways to the Umayyads.
Abbasid architecture is marked by a new monumental scale, the use of structural systems composed of massive brick piers and arches, and decoration of brick and carved and molded stucco. Moving the caliphal capital from Syria to Iraq, where they founded the new city of Baghdad, the Abbasids appropriated much of the eastern artistic traditions of the former Sasanian empire into their urban design and architecture.
After the caliphate of al-Mu'tasim and that of his son, al-Wathiq (842-47 / 227-32), the centralized power of the caliphate declined centrifugally. By 945, the area around Iraq fell to a dynasty of amirs , the Buyid dynasty. The 'Abbasids remained as caliphs until 1030, but they were only figureheads.
The Abbasid leadership was strong in the last half of the eighth century, with several competent caliphs and their viziers guiding the administrative changes. Military operations at this time were minimal, as the focus of the caliphate was on internal matters. Harun al-Rashid, caliph from 786 to 809, is particularly well known for his role in the famous collection of Arab and Persian fables, The Thousand and One Nights.
The 'Abassids only came to power with the help of diverse and disaffected populations; even though they consolidated power fairly ruthlessly in the beginning, their control over the world of Islam unraveled quickly. The first threat came with the establishment of Umayyad rule in Spain which, because of its distance, obviated any military reconquest of the area.
The first three centuries of Abbasid rule were a golden age in which Baghdad and Samarra’ functioned as the cultural and commercial capitals of the Islamic world. During this period, a distinctive style emerged and new techniques were developed that spread throughout the Muslim realm and greatly influenced Islamic art and architecture.
The Abbasid dynasty (750-1517 AD / 132-93 AH) seized political leadership of the Islamic world from the Umayyad caliphs in the middle of the eighth century, asserting their position as male descendants of Muhammad through his uncle, al-Abbas, to legitimize their claim to the caliphate.
The caliphate (632-1258) has traditionally been divided into three periods: the "Rightly Guided Caliphs" (632-661), the Umayyad empire (661-750), and the Abbasid empire (750-1258). During that time, a vast empire was created with successive capitals in Medina, Kufa, Damascus, and Baghdad. Stunning political success was complemented by a cultural florescence in law, theology, philosophy, literature, medicine, mathematics, science, and art.