Robert Kilwardby played an important part in the development of philosophy and theology in the thirteenth century. His lecture courses on logic, grammar, and ethics represent the most complete collection of works by one author that has survived to witness to what was taught in the faculty of arts at the University of Paris in the first half of that century. "Robert" was still being cited as an authority in grammar in the fourteenth century. His treatise De Ortu Scientiarum (On the Beginnings of the Sciences, circa 1250), written when he was a student of theology at Oxford, was widely read, as is clear from its existence today in some twenty manuscripts dating from the thirteenth to the fifteenth century; the son of Christopher Columbus purchased a copy in Spain in 1531. Kilwardby's Quaestiones in Libri Sententiarum (Questions on the Sentences, circa 1256), based on Peter Lombard's standard text in theology...