This paper will focus on court astrologers in early Abbasid Baghdad and argue that historical writing was largely delegated to them early on, before the subsequent rise of religious scholars who ultimately replaced them. This shift clearly reveals a profound turn in historical causality, as astrological histories were eventually rejected to the benefit of theocentric histories, and unveils the competition at work between scholarly circles. Such an inquiry will also shed new light on the thorny question of lost sources. Solid evidences show that astronomers/astrologers (the two categories overlap for the period under consideration) were heavily involved in historical writing during the early Abbasid period, and many of them produced astrological histories, i.e., historical narratives where planetary conjunctions (especially between Saturn and Jupiter) were the main engine fueling history. In so doing, they were largely following a Sassanian model. A large number of these astrological histories are unfortunately lost, but this paper will focus both on the extant sources and suggest fresh methodologies to get an access to lost texts. Special attention will be devoted to some of the key figures among those astrologers/historians as well as to the question of their legacy. Finally, this paper will also try to shed some light on the implications of such an astrological approach of history.