 The most lasting philosophical influence on Augustine is Neoplatonism. He does not specify the authors and the exact subjects of the “books of the Platonists” (Confessiones 7.13) translated into Latin by the fourth century Christian Neoplatonist Marius Victorinus (ib. 8.3) he read in 386. In the twentieth century there was an ongoing and sometimes heated debate on whether to privilege Plotinus (who is mentioned in De beata vita 4) or Porphyry (who is named first in De consensus evangelistarum 1.23 ca. 400) as the main Neoplatonic influence on Augustine (for summaries of the debate see O’Donnell 1992: II 421–424; Kany 2007: 50–61). Today most scholars accept the compromise that the “books of the Platonists” comprised some treatises of Plotinus (e.g., Enneads I.6, I.2, V.1, VI.4–5) and a selection from Porphyry (Sententiae and, perhaps, Symmikta Zetemata). In any event, the importance of this problem should not be overrated because Augustine seems to have continued his Neoplatonic readings after 386. Around 400 he had Porphyry’s Philosophy from the Oracles at his disposal; in De civitate dei 10 (ca. 417) he quotes from his Letter to Anebo and from an otherwise unattested anagogic treatise titled, in the translation used by Augustine, De regressu animae, the influence of which some have suspected already in Augustine’s earliest works. For the philosophy of mind in the second half of De trinitate he may have turned to Neoplatonic texts on psychology. While the exact sources of Augustine’s Neoplatonism elude us, source criticism has been able to determine some pervasive features of his thought that are doubtlessly Neoplatonic in origin: the transcendence and immateriality of God; the superiority of the unchangeable over the changeable (cf. Plato, Timaeus 28d); the ontological hierarchy of God, soul and body (Letter 18.2); the incorporeality and immortality of the soul; the dichotomy of the intelligible and the sensible realms (attributed to Plato in Contra Academicos 3.37); the non-spatial omnipresence of the intelligible in the sensible (Confessiones 1.2–4; Letter 137.4) and the causal presence of God in his creation (De immortalitate animae 14–15; De Genesi ad litteram 4.12.22); the existence of intelligible (Platonic) Forms that are located in the mind of God and work as paradigms of the sensible things (De diversis quaestionibus 46); the inwardness of the intelligible and the idea that we find God and Truth by turning inwards (De vera religione 72); the doctrine of evil as lack or privation of goodness; the understanding of the soul’s love of God as a quasi-erotic desire for true beauty (Confessiones 10.38; cf. Rist 1994: 155). A distinctly Platonic element is the notion of intellectual or spiritual ascent. Augustine thinks that by turning inwards and upwards from bodies to soul (i.e., from knowledge of objects to self-knowledge) and from the sensible to the intelligible we will finally be able to transcend ourselves and get in touch with the supreme being that is none other than God and Truth and that is more internal to us than our innermost self (Confessiones 3.11; MacDonald 2014: 22–26; Augustine’s biblical proof text is Romans 1:20, quoted, e.g., ib. 7.16). Ascents of this kind are ubiquitous in Augustine’s work (e.g., De libero arbitrio 2.7–39; Confessiones 10.8–38; De trinitate 8–15). Whether the condensed versions in the Confessiones (7.16; 7.23; 9.24–26) should be read as reports of mystical experiences is difficult to determine (Cassin 2017). An early version of the Augustinian ascent is the project—outlined in De ordine (2.24–52) but soon abandoned and virtually retracted in De doctrina christiana—of turning the mind to the intelligible and to God by means of a cursus in the liberal (especially mathematical) disciplines (Pollmann &amp; Vessey 2005). It is remotely inspired by Plato’s Republic and may have had a Neoplatonic precedent (Hadot 2005), though use of Varro’s work on the disciplines cannot be excluded (Shanzer 2005). As late as De civitate dei 8 (ca. 417) he grants, in a brief doxography organized according to the traditional fields of physics, ethics and epistemology, that Platonism and Christianity share some basic philosophical insights, viz. that God is the first principle, that he is the supreme good and that he is the criterion of knowledge (De civitate dei 8.5–8; cf. already De vera religione 3–7). In spite of these important insights, Platonism cannot however lead to salvation because it is unable or unwilling to accept the mediation of Christ. It is, therefore, also philosophically defective (De civitate dei 10.32).