 Siger of Brabant (d. 1284) and John of Jandun (d. 1328) were the best known and most influential Averroists. Siger, in his first and most explicitly Averroistic work on the soul, argues that the separate and eternal intellect is united to the body only in an operational union and that the true form of the body is the sensitive soul (Quaest. in tertium de anima, esp. q. 3 and 9). Under the influence of Thomas Aquinas and others, Siger later revised his position. For John of Jandun, the intellective soul, which in itself is one and separate, operates within the body. It is united to the body only through the assistance of the phantasmata (Brenet 2003). The Renaissance Averroists Agostino Nifo and Luca Prassicio argued that Siger and John of Jandun professed conflicting views: they interpreted Siger as holding that the unique intellect can be united to the body as form and John of Jandun that it cannot. Another influential Averroist was John Baconthorpe (d. 1345/48): He developed the theory of the so-called “double conjunction” (copulatio bifaria) between intellect and bodily phantasms: one epistemological, one ontological. The ontological conjunction presupposes a union of unique intellect and human being in a way that the intellect becomes a human faculty (Etzwiler 1971, 266–269). Among the most explicit and outspoken Averroists of the Renaissance were Nicoletto Vernia (d. 1499) and Luca Prassicio (d. 1533). The unicity thesis was successful among Latin authors not only because Averroes as the commentator had become an exceptional authority of university education, but also because it was attractive philosophically: it explained the possibility of the knowledge of universals and it ensured that the intellective soul, as demanded by Aristotle (De anima III.4, 429a22–25), was not mixed with the body.