 We have the names of five ancient interpreters (palaioi exêgêtai) of the Categories whose activity is placed in the 1st century BCE: Andronicus, Boethus, Athenodorus, Ariston, and Eudorus (Simplicius, In Cat. 159.32–33). It is likely that, of these five philosophers, only Boethus of Sidon wrote a commentary on the Categories. Boethus’ activity can be dated to the second half of the 1st century BCE. Simplicius contrasts his “word-by-word exegesis” to that of Andronicus, who is said “to have paraphrased the Categories” (Simplicius, In Cat. 29.28–30.5). We cannot exclude that Simplicius projected his own literary conventions onto Andronicus and Boethus, and that by his own standards Boethus and Andronicus were engaged in two different exegetical exercises. On the one hand, there is some clear evidence that Andronicus did rephrase and clarify Aristotle’s text in order to extract Aristotle’s intentions. On the other hand, there is no reason to think that Andronicus wrote in the style that will later be codified as paraphrase. Themistius was the champion of this particular form of exegesis in antiquity. Themistius does not give us names of predecessors. His silence is open to different interpretations: either Themistius did not know of Andronicus’ work on the Categories or this work was not written in the style of a paraphrase. Fortunately, it is not essential for us to establish whether or not Andronicus was the first paraphraser of Aristotle. What matters is that his style of exegesis was perceived as different from that of Boethus. Unlike Andronicus, Boethus was engaged in an in-depth examination of whole book of the Categories in the form of a word-by-word commentary. Boethus was highly regarded in antiquity. Simplicius refers to him as “the amazing Boethus” (In Cat. 1.18), “the noble Boethus” (In Cat. 379.32), and prizes “the sharpness of his mind” (In Cat. 1.23 and 434.18). Except for a few testimonies, his commentary has not survived. From these few testimonies, however, it is clear that Boethus concerned himself with the difficulties that the Stoics raised against Aristotle’s Categories. The Stoics attacked the Categories on the assumption that this treatise is on language and about linguistic expressions. They argued that as a treatise on language and about linguistic expressions the Categories was incomplete. Boethus resisted this reading of the Categories and anticipated a line of interpretation that was then followed, among others, by Porphyry. 