This thesis examines the nature and development of desire (particularly the Greek concept of erōs), through a selection of Marcus Cornelius Fronto’s letters, with a focus on desire within the relationship between Fronto and Marcus Aurelius, both educational and personal. While the relationship between Fronto and his pupil has been a topic of some interest since the early 2000s, this interest has mostly been biographical, and less focused on the implications of desire’s presence within the letters and the challenges this presence presents in terms of masculinity and the letters’ educational purpose. My goal is to explore erōs in these terms and to show that, in the way that desire comes to dominate both men’s writing, it is an essential part of any understanding of this collection as an educational text. To achieve this, my thesis will first discuss the connection between erōs and both education and masculinity in the Greco-Roman world, and the specific circumstances of masculinity in relation to the performance of oratory. From here, I will analyse the ways in which desire becomes a defining feature of both men’s writing, while also creating an almost inescapable paradox which threatens both Fronto and Marcus’ masculinity, and by extension status as orators. In the second half of this thesis I will then analyse the ways in which Fronto alters the terms by which erōs and rhetoric are discussed in order to achieve his goal of making rhetoric itself the object of Marcus’ erōs. This section will focus in particular on the ways in which Fronto changes the existing tropes and ideas which he and Marcus have used to describe their erōs to reframe it as desiring rhetoric in the abstract rather than the physical form of the orator.