Abbasid caliph Müstain Billah and his period (m.862-866).

The Abbasids are a focus of great interest in current historical research. Many caliphs who ruled the Abbasid dynasty for 508 years were led by researchers. In order to understand the development of Abbasid, it is necessary to examine his caliph in detail. In particular, it will help us better understand the recorded political structures of the caliph Müstain Billah and his period, who were in power in the second known century of the Abbasids, which is an important period in Islamic history. The Müstaîn period has generally been neglected as a separate research topic in the literature review. A detailed examination of this period is important in order to fully understand the initial period. In this thesis, the Abbasid caliph Müstaîn Billâh and his period are discussed in general terms. In the research, the data of historical sources that shed light on this period were scanned and the obtained data are presented chronologically.