 Grosseteste’s so-called metaphysics of light rests on a hylomorphic (matter-form) account of the metaphysical makeup of bodies. On this basis Grosseteste explains the generation and nature of the cosmos. Grosseteste also interprets aspects of Aristotle’s natural philosophy in terms of this theory.  He sets out this theory most fully in On Light, but elements of it are present also in his commentaries on the Posterior Analytics and  Physics, in On Bodily Movement and Light, and in his commentary on Ecclesiasticus 43: 1–5, also known as On the Operations of the Sun. 