Commentaries on ancient texts represent the quintessential product of Byzantine school education, being also a privileged site for displaying polemics and rivalries between exegetes. In twelfth-century Constantinople, John Tzetzes’ authorial voice stands out in this respect. Among his extensive exegetical production on classical texts, the present chapter focuses on his mostly unedited Commentary on Hermogenes’ Stas., one of the most important treatises among the four “Hermogenian” works within the curriculum taught in Byzantium. In Tzetzes’ Commentary—only partially published and preserved in full by the twelfth-century manuscript Leiden, Universiteitsbibliotheek, Vossianus Graecus Q1—critiques against previous exegetes, ancient authors, and Hermogenes himself become a means of self-affirmation in the eyes of patrons and sponsors. Unlike other commentators, Tzetzes reinforces his exegetical voice by adopting the stance of another theoretician, possibly a contemporary of Hermogenes, namely Minucianus, whose views on rhetoric are contrasted with Hermogenes’ approach. By looking specifically at the occurrences of the name of Minucianus in the marginal notes of the Leiden manuscript, this contribution aims to demonstrate that this rhetor was particularly important to Tzetzes. Tzetzes takes Minucianus as his main authority on a set of crucial topics for which the latter’s approach was fiercely criticized by Hermogenes, with Tzetzes going so far as to establish a personal correspondence with him.