 Just as the late-antique Platonists developed their cosmological thinking by commenting on Plato’s Timaeus, Augustine’s natural philosophy is largely a theory of creation based on an exegesis of the opening chapters of Genesis, on which he wrote five extended, and occasionally diverging, commentaries (De Genesi contra Manichaeos; De Genesi ad litteram liber imperfectus; Confessiones 11–13; De Genesi ad litteram; De civitate dei 11–14). The longest and most important of them is the Literal Commentary on Genesis (De Genesi ad litteram). “Literal” does not mean “literalist” but denotes the hermeneutic assumption that the text is really about the creation of the world (as opposed to a moralist or prophetic allegorical reading of the kind proposed in Augustine’s early De Genesi contra Manichaeos; the two approaches are compatible because Augustine, like Origen and the Jewish exegete Philo before him, believes in the existence of multiple layers of meaning in Scripture; see De Genesi ad litteram 1.1.1 and, in general, De doctrina christiana, bk. 3). In line with his epistemology of illumination and his theory of verbal signs,  Augustine takes the biblical creation tale as an “admonition” that prompts him to devise, with the help of the “inner teacher”, a rational theistic cosmology based on Trinitarian theology (for rejection of explanations that contradict the findings of the natural philosophers or the laws of nature cf., e.g., De Genesi ad litteram 2.9.21). In De Genesi ad litteram, in the Confessiones and, to a lesser extent, in De civitate dei Augustine presents his exegesis in a questioning manner and keeps the results open to revision. The reason is that, according to the hermeneutics developed especially in bk. 12 of the Confessiones, the authorial intention of the Scriptural text, or indeed of any text, cannot be recovered, so that—given that the truthfulness of Scripture can be taken for granted—different and even incompatible readings must be considered as adequate if they agree with what the text says and if they are sanctioned by the truth which we access inwardly through reason and which is, ultimately, God himself (see esp. Confessiones 12.27; 43; De doctrina christiana 3.38 where Augustine claims that the Holy Spirit providentially allowed for a plenitude of Scriptural meanings in order to prompt different people to different aspects of the truth; Williams 2001; van Riel 2007; Dutton 2014: 175–179; and, on the epistemological foundations of this hermeneutics, Cary 2008b: 135–138). The basic and recurrent features of Augustine’s cosmological thought are these (cf. Knuuttila 2001: 103–109; Mayer 1996–2002, each with references): God does not create in time but creates time together with changeable being while resting in timeless eternity himself (Confessiones 11.16; De Genesi ad litteram 5.5.12; the distinction of eternity and time is Platonic, cf. Timaeus 37c-38b; Plotinus, Enneads III.7.1). Creation occurs instantaneously; the seven days of creation are not to be taken literally but are a didactic means to make plain the intrinsic order of reality (Confessiones 12.40; De Genesi ad litteram 1.15.29). Like the demiurge in the Timaeus, God creates out of goodness, i.e., out of his good will and his gratuitous love for his creation (De civitate dei 11.24). In creation, all three persons of the Trinity are active, with, roughly, the Father accounting for the existence, the Son (to whom, in Augustine’s reading, the opening words of Genesis, in principio, refer) for the form or essence and the Holy Spirit for the goodness and orderliness of every created being (Confessiones 11.11; De civitate dei 11.24). As the causality of the Trinity makes itself felt everywhere in creation, Augustine likes to describe created beings in their relation to the divine cause in a triadic manner, using, e.g., the categories “measure”, “form” and “peace/order” (e.g., De vera religione 13; De natura boni 3; De civitate dei 12.5; cf. Schäfer 2000 and, for a very thorough discussion, du Roy 1966). These “traces” of the Trinity in creation must not be confused with the Trinitarian structure of the human intellect, which, alone among all created beings, is an image of God.  Changeable being is not generated from God (which, according to the Nicene Creed, is true only of the Son) but created out of nothing, a fact that partly accounts for its susceptibility for evil.  More precisely, God “first” creates formless matter out of nothing (which is why matter in Augustine, unlike in the Neoplatonists, has a minimal ontological status; cf. Confessiones 12.6; Tornau 2014: 189–194) and “then” forms it by conveying to it the rational principles (rationes) that eternally exist in his mind (De diversis quaestionibus 46.2) or, as Augustine prefers to put it, in his Word, i.e., the Second Person of the Trinity. This formative process is Augustine’s exegesis of the biblical “word” of God (Genesis 1:1 and John 1:1). Incorporeal and purely intellectual beings, i.e., the angels, are created from intelligible matter which is created out of nothing and converted to the creator so as to be formed through the “hearing” of God’s word, i.e., by their contemplation of the Forms contained in God (De Genesi ad litteram 1.4.9–1.5.11, an idea inspired by the Neoplatonic pattern of abiding, procession and return). Corporeal being is created when the Forms or rational principles contained in God and contemplated by the angels are even further externalized so as to inform not only intelligible but also physical matter (De Genesi ad litteram 2.8.16; 4.22.39).