were a number of "commentaries" on the Sentences, but Alexander's appears to have been the first magisterial commentary. Although it was Alexander's most significant writing, it had not been completed, therefore leaving historians with many questions on the reliability and quality of the writing. This was taken into consideration when the Summa had been examined by Victorin Doucet for different editions of them. The sources has seem to be the resulting problem of the Summa, "counted there were 4814 explicit quotations and 1372 implicit quotations from Augustine, more than one quarter of texts were cited in the body of the Summa. Of Alexander's Summa, which was on one occasion proclaimed by an assembly of seventy doctors to be infallible, Roger Bacon declared that, though it was as heavy as the weight of a horse, it was full of errors and displayed ignorance of physics, of metaphysics, and even of logic. Other historical works Alexander also influenced and sometimes is confused with Alexander Carpenter, Latinized as Fabricius (fl. 1429), who was the author of the Destructorium viciorum, a religious work popular in the 15th and 16th centuries. Carpenter also authored other works, such as "Homiliae eruditae" ("Learned Sermons"). Historiographical contribution Alexander was said to have been among the earliest scholastics to engage with Aristotle's newly translated writings. Between 1220 and 1227, he wrote Glossa in quatuor libros Sententiarum Petri Lombardi (A Gloss on the Four Books of the Sentences of Peter Lombard) (composed in the mid-12th century), which was particularly important because it was the first time that a book other than the Bible was used as a basic text for theological study. This steered the development of scholasticism in a more systematic direction, inaugurating an important tradition of writing commentaries on the Sentences as a fundamental step in the training of master theologians. A medieval scholastic In doing so, he elevated Lombard's work from a mere theological resource to the basic framework of questions and problems from which masters could teach. The commentary (or more correctly titled a Gloss) survived in student reports from Alexander's teaching in the classroom and so it provides a major insight into the way theologians taught their discipline in the 1220s. As is the case with Glossa and Quaestiones Disputatae, much of his work is probably written in the form of notes on his oral teachings by students, though the content is definitely his. For