This study aims to track the development of the system of succession in the first Abbasid Age (132-247 AH/ 750-861 AD) and focuses on the most important events resulting from that system. It, also, discusses the role of the court men and women in this case. The researcher relied on some primary sources and some up to-date and modern references that discussed this case. She also adapted the * historical approach which depends on describing and analyzing historical stories as well as comparing opinions of modern contemporary historians on this particular subject. This study contains an introduction, preface, three chapters and a conclusion. The first part introduced the study, its aims and significance, review of the literature regarding the same issue and mentioned the three chapters and its components. In the preface however, some general information about the system of succession before Abbasid Caliphate (132 AH/ 750 AD) were given. The first chapter discussed the system of succession in the state foundation period (132-158 AH/ 750-775 AD). The second chapter, however, focused on the system of succession in the period of stabilization, civilization and prosperit (158-193 AH/ 775-809 AD). The last chapter investigated the intensified conflict and state of the mandate of succession at the end of the first Abbasid Age (193–247 AH/ 809-861 AD). The study concluded that Abbasid followed the system of inherited succession and it was solely applicable for the Abbasid tribe which causes conflicts and arguments among Abbasid family such as Abdullah bin Ali Rebellion and the war between Al-Ameen and Al-Mamoon. It is also noticed that Abbasid Caliphs Commandments had political and religious values. One obvious conclusion was that the retinue and courts men and women had a very important role in the mandate of succession which depended on the personality of the caliph.