This chapter explores Shakespeare’s knowledge and use of the European ius commune. The ius commune was the amalgam of Roman and canon law taught in Europe’s universities, including England’s, and employed as the basic source of law in European legal tribunals to the eighteenth century. It was applied in the courts of the English church, the Admiralty, the universities, and some of the courts of equity that had come to life in the sixteenth century. These courts were served by a separate legal profession, the English civilians. Recent interest in Shakespeare’s knowledge and use of law takes virtually no notice of this aspect of English law. This chapter demonstrates a number of points. The first is that Shakespeare was familiar with the ius commune. He used its terminology and then made something of it in the dialogue of his plays. The second is that this knowledge had results in their thematic coverage. He employed his knowledge of the ius commune to shape and enrich the substance of the plays. The third is that his use of the civil and canon laws was connected with areas of contemporary controversy in England.