 Relying on manuscript evidence and other sources, Giorgio Pini (2005) could identify which kind of theological and philosophical works Giles read, studied and had copied for himself during his long intellectual career. Pini distinguishes three main periods. In the first one, before 1277, quite unsurprisingly, he reads Aquinas (not only the Commentary on the Sentences of the Dominican master, but also his later works), Aristotle (e. g. in these years Giles owns and annotates a copy of the Nicomachean Ethics), Avicenna and Averroes. He is also very well acquainted with the works of Ps. Denis the Aeropagite. In the second period (1277–1285), when forced to leave the academic milieu, Giles widens his interests. He studies many works of Anselm’s (while most theologians of his time were very selective in their knowledge of this author), and makes acquaintance with works by Augustine, such as Confessions and Soliloquia, that were quite unusual readings for an academic theologian. In the this period (from his return to the Parisian Faculty of Theology [1285] to his death) Giles studies almost entirely the available works by Augustine and acquires also rare treatises by Proclus. Giles’ increasing attention for Augustine is mirrored in his mature works and will influence also the theological orientation of his own Order in the following decades (Pini 2012).