 Some Christian Arabic philosophers working in the 9th and 10th centuries give evidence of having exerted their ’influence’ upon Medieval Judaic thought. The first of them was Abd al-Masih Ibn Na‘ima al-Himsi, a collaborator of al-Kindi: his famous Arabic philosophical work, the “shorter version” of the Theology of Aristotle (a reworking of parts of books four, five, and six of Plotinus’ Enneads), as well as other Arabic texts connected to it (the Sayings of the Greek Sage, the De causis and pseudo-Empedocles’ Book of the Five Substances), might have exerted their direct influence over Solomon Ibn Gabirol, as suggested by Jacques Schlanger (see Schlanger 1968, 52–109). Moreover, a “longer version” of the Theology of Aristotle might have been written by a Judaeo-Arabic scholar in 10th- or 11th-century Egypt: it was apparently quoted by Shem Tov Ibn Falaquera (Langermann 1999), who in any case knew and employed also the “shorter version” of it (Fenton 1992), and was translated into Hebrew in the 16th century by Moses Arovas (about this translation, now lost, see Fenton 1986). Falaquera wrote also a summary of the Book of the Five Substances (edited in Kaufmann 1899, 17–37), which proves to be useful for reconstructing the contents of the lost original text (see the French translation by Győngy Hegedüs in De Smet 1998, 208–231). The main role in influencing Jewish philosophy was played by the De causis, an Arabic work mixing up some aspects of Plotinus’ and Proclus’ theology and probably written in the 9th century in al-Kindi’s circle by a still unidentified author (a Christian-Arabic one?): it was translated into Hebrew four times in the period 1260–1480, and exerted its ‘influence’ over a number of Jewish philosophers (see Rothschild 1985, 1994).