This essay investigates the rhetoric of royal imprisonment in Ane Detectioun of the duinges of Marie Quene of Scottes (1571), one of the most famous contemporary texts associated with the Marian controversy. This Anglo-Scots pamphlet not only invokes Mary’s actual incarceration but also represents her as a captive of erotic desire, a slave of unruly passion, and a prisoner of the law. This multifaceted vision of royal incarceration is animated by a heterogeneous tradition of ideological writing in medieval and early modern England and Scotland. Three strands of a rich mosaic of interlocking discourses are analyzed: the imagery of a ruler imprisoned by passions found in Boethius’s Consolatio; a courtly love allegory in which royal eros submits to the bondage of legal constraint in The Kingis Quair; and the figurations of limited monarchy as royal incarceration in the Anglo-Scots political philosophy of John Fortescue and George Buchanan. Much more than a broadly gendered metaphor for queenly submission, this language of royal imprisonment derives its legitimacy from discourses that touch upon the very ideological foundations of English and Scottish monarchy.