The Astrological and Prophetical Cycles in the Pseudo-Aristotelian Hermetica and in the Ikhwān al-Ṣafā’

Astrological cycles are an important motif in the corpus of writings known as Pseudo-Aristotelian Hermetica (PsAH), especially in the treatise entitled Kitāb al-Ustuṭās. Therein, we find a highly elaborated cosmic scheme accounting for various processes of generation and renewal in the universe as dependent on the cyclical revolutions of the zodiac and the planetary spheres. According to this scheme, the history of the world is divided into 12 ‘ages’ of decreasing length, each age corresponding to a zodiacal sign. Starting with the age of Aries, it assumes that Adam, the father of mankind, was created by the demiurge in Virgo, the seventh age, after the generation of minerals, plants, and animals in preceding ages. The scheme also assumes that civilization itself was introduced to the human kind by seven prophets, each corresponding to a specific planet, and that these prophets in turn endowed their people with the power to control nature. Furthermore, the generation of active spiritual forces (ruḥāniyyāt) is regulated by 1000-year cycles. In its long version, the epistle on magic, which concludes the encyclopaedic corpus of the Ikhwān al-Ṣafā’, acknowledges its debt to the Kitāb al-Ustuṭās and even quotes from it in a long passage on the lunar mansions. In more general terms, the Rasā’il (and the Risāla al-Jāmi‘a) attach great importance to a conception of the world history according to which prophetical ages, expressed as millenary periods, are determined by the revolutions of the seven planets. The purpose of this paper is to compare these texts, and to determine to which extent the PsAH were a resource to the Ikhwān’s prophetical astrology. We shall also seek to situate this investigation against the broader context of astrological history in medieval Islam as exemplified by Abū Ma‘shar, Māsha’allāh and others