Threatened with rape during a pivotal episode of the Man of Law's Tale, Chaucer's Custance offers fierce resistance, 'struglyng wel and myghtily' (IL921) with her assailant.1 In this moment, she acts in a way that strikes modern readers as utterly instinctive and natural, but which is nonetheless remarkable as 'the only instance ... in Chaucer, of a woman fending off rape by her own physical efforts'.2 The outcome of the struggle, which takes place as Custance's rudderless boat drifts off the coast of Spain, is even more remarkable, as it culminates with her assailant falling into the sea to his death.3 While the death of the rapist appears in Chaucer's most direct sources (the versions by Trevet and Gower), Custance's physical resistance to rape is markedly and designedly different from these sources, and significantly alters the tone and implications of the scene.^ In a brief but illuminating account of this passage, Corinne Saunders comments on the 'coincidence of physical and spiritual resistance against rape' in Chaucer's account, noting that Custance's use of force is explicitly supplemented by the divine assistance of Mary and Christ (II.920-4). Saunders highlights the biblical and hagiographical parallels for this, noting that the pairing of physical and spiritual resistance 'distinguishes the tale of Custance, like those of Judith, Christina and Winifred, from earlier hagiographical examples' (p. 286). While these saintly parallels to Custance's active heroism are useful and suggestive, it is fair to observe that none of them offers an entirely precise analogy: while the villain of the Old English Judith (to which Saunders is here referring) expresses a desire to violate the heroine, the actual slaying of Holofernes does not take place in the direct context of resisting rape; moreover, neither Christina of Markyate nor St Winifred engage directly in any action that leads to the death of their adversaries. The present account offers an alternative but complementary way of thinking about Custance's resistance by interpreting the scene in the context of legal and ethical arguments about the permissibility of killing in self-defence, specifically in order to prevent rape. Read in dialogue with each other, the accounts of the attempted rape in Trevet, Gower, and Chaucer reflect striking disagreements in relation to the heroine's use of force. While Trevet unapologetically asserts Constance's right to kill her assailant, Gower appears to baulk at the suggestion, radically altering the events of the scene to minimize Constance's agency, while heightening the role of divine intervention. I will suggest that Chaucer's modifications of this scene not only demonstrate familiarity with contemporary self-defence law but also advance a challenging hypothesis: namely that the right to kill in self-defence, well established in English law at the time, extends to a woman's right to use lethal force to prevent rape, and is not limited to a person's right to use such force to prevent death. To this end, the final section of this analysis will offer a detailed comparison of the attempted rape in the Man of Law's Tale with its sources and analogues, situating Custance's struggle within the legal and moral framework of selfdefence, the principles of which are outlined in the second section. My analysis begins, however, with an examination of how Chaucer's other works characterize the threat of rape and the possibility of physical resistance, providing essential context for understanding the legal, ethical, and cultural debates that underpin Chaucer's characterization of the attack on Custance and her response to it.5IIn order to understand the remarkable nature of Custance's resistance to rape (and the even more remarkable consequences of that resistance), it is necessary to distinguish the attack on the Christian heroine of the Man of Law's Tale from the sexual assaults perpetrated against the pagan heroines of the legends of Lucrece and Philomela in The Legend of Good Women. …