  Alexander of Aphrodisias (fl. 200 CE) was influential in pushing the separate-and-divine reading of De anima III.5, and Islamic philosophers (most notably Ibn Sīnā [980–1037] and Ibn Rushd [c.1126–c.1198]) would later follow suit. Themistius (4th century CE), in contrast, championed the part-of-soul reading, and Thomas Aquinas (1225–1274) would second this interpretation. A full treatment of this topic would cover the later Aristotelian and Platonic traditions, Greek and Islamic. But here I will focus exclusively on the Latin West, where it was Augustine who played the decisive role in formulating the doctrine of illumination. (For a useful survey of ancient and medieval Aristotelian accounts of agent intellect, see Brentano 1992. On the later Platonic tradition, see Gersh 1978. The Islamic tradition deserves a full essay in its own right, covering not just names well known in the Latin West, but also figures like Suhrawardi and Mulla Sadra, central figures in the Islamic illuminationist tradition [see Walbridge 2005].)