 Richard Rufus and Roger Bacon were two of the earliest Teachers of Aristotle’s natural philosophy and metaphysics at Paris, c. 1235–50. The recent publication of Richard Rufus of Cornwall’s In Physicam Aristotelis has made available what is certainly a very important text for an understanding of the influence of Aristotle’s Physics on the early tradition of English natural philosophy in the thirteenth century (IPA 2003). Richard Rouse has dated the text of these Physics questions “on the early side of the middle of the century” (Wood, IPA Introduction, 33). Silvia Donati and Cecilia Trifogli have mapped out the complex tradition of named and ‘anonymous’ commentaries on Aristotle’s Physics in 13th century England. (Del Punta, Donati &amp; Trifogli 1996; Trifogli 1997, Donati 1997; Trifogli 2000). As noted above, Rega Wood ascribes the text to Richard Rufus of Cornwall (died c. 1260). She claims that “Richard Rufus was the earliest Western teacher of the new Aristotle whom we know.” He taught Aristotelian physics and metaphysics as a Master of Arts at the University of Paris before 1238. In the apparatus of the edition, Wood notes that these comments on Aristotle’s Physics were later taken up by Roger Bacon in his Questiones on Aristotle’s Physics, and as a result, she sees Roger Bacon as Richard Rufus’s successor as a Parisian teacher of Aristotle’s natural philosophy. As evidence for the influence of Rufus on Roger Bacon, Wood presents a discussion of three topics: (1) projectile motion, (2) the place of Heaven, and (3) the beginning of the world (IPA, 12–28).