This is a study of marriage litigation in the archiepiscopal court of York (1300–1500) and the episcopal courts of Ely (1374–1381), Paris (1384–1387), Cambrai (1438–1453), and Brussels (1448–1459). All these courts were, for the most part, correctly applying the late medieval canon law of marriage, but statistical analysis of the cases and results confirms that there were substantial differences both in the types of cases the courts heard and the results they reached. Extensive additional material—over 300 pages—can be found on the Cambridge University Press website (www.cambridge.org/9780521877282) in the Resources and Solutions section under the heading "Text and Commentary". This additional material includes Latin quotations from cases, discussions of alternative interpretations, references to primary sources that support the argument and references to the literature on the cases.