 In reality, the conciliation of Plato and Aristotle attempted by these commentators consisted in an appropriation of Aristotle’s works as a pre-requisite for the study of Plato’s philosophy. Among these works, the Categories continued to enjoy a special status. Following a tradition that may go all the way back to Andronicus of Rhodes (see the section on the early fortune of the Categories), this treatise was considered an elementary introduction to the whole of philosophy and as such it was used to teach beginners with little or no knowledge of philosophy (Porphyry, In Cat. 56. 28–29). For this reason the exegetical activity on this short but difficult treatise never stopped but in fact increased in Late Antiquity. The key figure for the reception of the Categories during this period was undoubtedly Porphyry (ca 234–305 CE). The latter wrote a commentary in seven books addressed to a student named Gedalius. In this commentary, Porphyry offered a complete interpretation of the Categories, including a resolution of all previous aporiai (Simplicius, In Cat. 2. 6–9). He also dealt with the traditional criticism of the Categories, including a comprehensive discussion of the objections leveled by the earlier interpreters of the Categories (e.g., the Stoic Athenodorus and Cornutus, and the Platonic Lucius and Nicostratus). His defense of the Categories relied, and indeed expanded, on the Peripatetic tradition (e.g., Boethus of Sidon, Alexander of Aphrodisias). An excerpt from this commentary has been recently discovered in what is known as the Archimedes Palimpsest (See R. Chiaradonna, M. Rashed, and D. Sedley 2013). Porphyry wrote another commentary on the Categories. This second commentary has reached us. The results achieved in the more comprehensive commentary are here abbreviated, simplified, and made accessible in the form of a dialogue between a teacher and a pupil. The existence of two commentaries written in a different format on the very same treatise by the same author has to be understood in the light of the fact that these commentaries were teaching tools and were used to teach students with different skills and different levels of familiarity with the Categories. Finally, Porphyry is the author of the Isagoge (literally, “Introduction”). This short book is an introduction to Aristotle’s theory of predication. It is addressed to absolute beginners in philosophy whose reading curriculum then continued with Aristotle’s logic, beginning with the Categories.