Chapter 1 draws on Julian’s earliest surviving oration – the Letter to Themistius – to illustrate the interaction between Julian’s early rhetoric and the political discourse developed at the court of Constantius II. The first section challenges scholarly readings of the Letter as voicing a rejection of the late antique ideal of the sovereign as ensouled law. It argues that Julian’s primary intent in this text lies rather in a desire to advertise his exegetical skills at the expense of his interlocutor, the famous philosopher Themistius. The second sectio contextualises Julian’s ambition in the context of third- and fourth-century debates on the relationship between leadership and culture. It shows that this theme was invested with particular significance by Christian authors – such as Lactantius and Eusebius – who used it in claiming Christianity’s intellectual dominance over pagan thinking. This testifies to the existence of a shared perception that cultural authority legitimised political authority but also signals the ambitions of Christian intellectuals to negotiate Christianity’s cultural prestige in conversation with the Roman elites.