Ar: al-Abbasiyah, is the second major Muslim dynasty (750-1258 A.D.) ruling after the Umayyads. Its capital is Baghdad and during this period, much developments ensued. The dynasty began with Abbas, an uncle of Muhammad. Because of his close relation with Muhammad, they were held in high esteem by the Arabs, and much dispute occurred between them and the Ummayyads. Having asserted their claims to the Caliphate for some time, they commenced open hostilities in 746 A.D. Abu `l-Abbas as-Saffah ("the blood shedder") defeated the Ummayad Caliph Marwan II and became the Caliph at al-Kufa in 749 A.D. and Marwan II was slained.
List of Abbasid Caliphs:
A.D. 749 Abu 'l-Abbas as-Saffah A.D. 754 al-Mansur A.D. 775 al-Mahdi A.D. 785 al-Hadi A.D. 786 Harun ar-Rashid (see below) A.D. 809 al-Amin A.D. 813 al-Ma'mun A.D. 847 al-Mutawwkil A.D. 861 al-Muntasir A.D. 862 al-Mustain A.D. 866 al-Mu`tazz A.D. 869 al-Muhtadi A.D. 870 al-Mu`tamid A.D. 892 al-Mu`tazid A.D. 902 al-Muktafi A.D. 908 al-Muqtadir A.D. 932 al-Qahir A.D. 934 ar-Razi A.D. 940 al-Muttaqi A.D. 944 al-Mustagfi A.D. 945 al-Muti` A.D. 974 at-Tai` A.D. 994 al-Qadir A.D. 1031 al-Qaim A.D. 1075 al-Muqtad A.D. 1094 al-Mustazhir A.D. 1118 al-Mustarshid A.D. 1135 ar-Rashid A.D. 1136 al-Muqtafi A.D. 1160 al-Mustanjid A.D. 1170 al-Mustaz A.D. 1180 an-Nasir A.D. 1225 az-Zahir A.D. 1226 al-Mustansir A.D. 1242 to 1258 al-Musta`sim
During al-Musta`sim's reign, the grandson of Ghengis Khan, Hulaku, entered Persia and became Sultan in A.D. 1256. In 1258, he captured Baghdad and put to death al-Musta`sim.
Harun al-Rashid is probably the most famous of these Caliphs, partly because of the tales of 1001 Nights. For more background on his person and reign, see What was and what might have been – The "Golden Age" of Harun Al-Rashid.