Introduction The practice of astrology during theʿAbbāsid period represents an important aspect ofthe political, social, and cultural life of thisdynasty, and for this reason it is a subject worthyof study for modern historians. Yet in spite of therich secondary literature on Arabic astrology, thesocial and institutional circumstances under whichʿAbbāsid astrologers operated remain poorlyunderstood. The most insightful treatments of thistopic remain the brief discussions by D. Gutas andG. Saliba, both published in the 1990s. By buildingon these two studies, the present article seeks toprovide a picture of the patronage networks andastrological practices existing during the caliphateof al-Maʾmūn (r. 197/813–218/833). After a briefoverview of the ʿAbbāsid patronage of astrologybefore this caliph's reign, the study focuses on thebiographical information connecting al-Maʾmūn withthis discipline and provides a list of the Arabicastrologers employed by this caliph, therebyshedding light on a key feature of his intellectualbiography and his courtly and scientific entourage.In the final section of the article, theinstitutional context in which ʿAbbāsid astrologersoperated is addressed, especially in connection withthe socalled “House of Wisdom” (Bayt al-Ḥikma). My aim is to tackle somebasic questions related to astrological practice andpatronage and to illuminate with greater precisionthe social implications of astrology in the earlyʿAbbāsid courtly context as these notions aredepicted in the primary sources. The present studyrepresents a first step towards reconstructing theanthropological and institutional environmentsurrounding the practice of astrology during thecaliphate of al-Maʾmūn.

11.2 ʿAbbāsid Astrological Patronage in thePeriod before al-Maʾmūn

In the following paragraphs, I discuss theprosopographic and biographi- cal evidence that hassurvived concerning al-Maʾmūn and the astrologers heemployed. Indeed, an important preliminary step forour understanding of al-Maʾmūn's patronage ofastrology is to identify the various scholars in hisemploy and the kind of works they were commissionedto execute for their patron. In order to sketch sucha picture, I have relied both on medieval works andmodern studies, and I have striven to merge theinformation they contain into a list (providedbelow).