Justice and mercy argues that our understanding of the creation of the English common law cannot be complete until we appreciate the moral dilemmas the process generated. It investigates one of the most acute difficulties facing the judges of the twelfth century: how to choose between justice and mercy when determining the appropriate punishment for an offender. This choice was particularly troubling because a morally wrong decision could endanger the soul of the judge making it. This book therefore provides a new way of thinking about the English common law by reconstructing the moral world of the judges themselves. Examining a wide range of texts, including theological commentaries, moral treatises, letters, sermons and chronicles, the book shows how concern over judicial probity, virtue and behaviour was not only an important debate in twelfth-century England, but central to much of English politics, from the Anarchy to the Becket dispute, from the laws of Henry I to the pardons of Henry III. It redraws the relationship between English judges and their continental counterparts, offering new reflections on shared influences and points of divergence. In doing so, it provides a fundamentally different narrative of the creation of the common law and a new way of understanding the implications of legal systematisation. Justice and mercy will be invaluable to specialists examining the rise of ‘professional’ law in the twelfth century and the beginnings of official accountability. It will also be of interest to students studying the creation of the common law, the twelfth-century renaissance and the structures of medieval English politics and kingship.