In classical descriptions, Persians and their rulers are seen as being given to both tyranny and femininity; early modern Europe thus inherited a view of Persia in which the performance of religious identity, political power and gender were inter-connected. Given the complex relationships between Islam, tyranny and gender, early modern European interest in the possible religious conversion of Persia and its people marks a moment at which contemporary anxieties about religious and gender identities converge. This chapter argues that European writers’ interest in the prospect of Persian conversion became tied up with their ideas about the links between Persian effeminacy and tyranny. The prospect of the conversion of Persian Shahs in early modern travel literature and drama gives rise to particular anxieties about masculinity, both in Persian figures and in the Christian European travellers and dramatists who portrayed them. Despite the tradition of viewing Persia as feminised and luxurious, the sources betray an underlying concern that Muslims’ gender and religious identities might in fact be more ‘fixed’ than those of Christian travellers, who experienced their own conversions to Islam and to Persian identities in ways that were troubling to them both as Christians and as men.