 Averroes composed Long, Middle, and Short commentaries on Aristotle’s Physics and some essays, masā’il, quaestiones, on physical matters. The Middle and Short commentaries were revised by Averroes himself, and the Long Commentary shows traces of revision, but in general, the Long Commentary represents the last stage of his thought. The Middle Commentaries were favored by later Jewish philosophers, but, as S. Harvey has shown, the Long Commentary on the Physics was soon translated into Hebrew and also drew their interest (Harvey 1985). The Long Commentary was the most influential of the three in the Latin West and a recent collective publication highlights its influence in the field of natural philosophy (Bakker 2015). For this reason the research for this article will rely mainly on it, but occasional references to the other commentaries, or to other works, will be made.