Isagoge

… and of Porphyry of Tyre’s Isagoge (“Introduction,” on Aristotle’s Categories), although these translations were not very influential. He also wrote logical treatises of his own. A short De dialectica (“On Dialectic”), doubtfully attributed to St. Augustine (354–430), shows evidence of Stoic influence, although it had little influence of its own.…

… and De interpretatione and Porphyry’s Isagoge, together with the commentaries and independent treatises by Boethius.

…with a short introduction (Isagoge). The Isagoge, in fact, is only concerned with a simple and rather mechanical treatment of five concepts that had been much used by Aristotle. These were the concepts of genus, or kind (as animal is the genus, or kind, under which Socrates falls); species,…

The study of Porphyry’s Isagoge, of Aristotle’s Categories and De Interpretatione, and of theological texts containing Aristotelian elements formed the basis, from the 9th century onward, of logical methodology (dialectic) in a wide number of fields. When applied to problems concerning the Trinity or the Eucharist, or in general…

…before 510 to translate Porphyry’s Eisagogē, a 3rd-century Greek introduction to Aristotle’s logic, and elaborated it in a double commentary. He then translated the Katēgoriai, wrote a commentary in 511 in the year of his consulship, and also translated and wrote two commentaries on the second of Aristotle’s six treatises,…

…commentaries and glosses on Porphyry’s Isagoge and on Aristotle’s Categories and De interpretatione; these were the Introductiones parvulorum (also containing glosses on some writings of Boethius), Logica “Ingredientibus,” and Logica “Nostrorum petitioni sociorum” (on the Isagoge only), together with the independent treatise Dialectica (extant in part). These works show a…