War is a major theme in Shakespeare’s plays. Aside from its dramatic appeal, it provided him with a context in which his characters, steeped in the ideals of chivalry, could discuss such concepts as honor, courage, patriotism, and justice. Well aware of the decline of chivalry in his own era, Shakespeare gave his characters lines calling for civilized behavior, mercy, humanitarian principles, and moral responsibility. In this remarkable new book, eminent legal scholar Theodor Meron looks at contemporary international humanitarian law and rules for the conduct of war through the lens of Shakespeare’s plays and discerns chivalry’s influence there. The book comes as a response to the question of whether the world has lost anything by having a system of law based on the Hague and Geneva conventions. Meron contends that, despite the foolishness and vanity of its most extreme manifestations, chivalry served as a customary law that restrained and humanized the conflicts of the generally chaotic and brutal Middle Ages. It had the advantage of resting on the sense that rules arise naturally out of societies, their armed forces, and their rulers on the basis of experience. Against a background of Medieval and Renaissance sources as well as Shakespeare’s historical and dramatic settings, Meron considers the ways in which law, morality, conscience, and state necessity are deployed in Shakespeare’s plays to promote a society in which soldiers behave humanely and leaders are held to high standards of civilized behavior. Thus he illustrates the literary genealogy of such modern international humanitarian concerns as the treatment of prisoners and of noncombatants and accountability for war crimes, showing that the chivalric legacy has not been lost entirely. Fresh and insightful, Bloody Constraint will interest scholars of international law, lovers of Shakespeare, and anyone interested in the history of war.