The fourth chapter discusses the question of why now – why did customary law become the subject of vigorous written output at this particular thirteenth-century moment? The answer lies in the politics of customary law or, more specifically, the changes in both society and legal culture that created new zones of competition between secular and ecclesiastical courts. Competition between the temporal and spiritual jurisdictions was, of course, not new. The investiture controversy that began in the eleventh century, based in the conflict over the right of appointment of church officials, showed this to be a key issue of the high medieval period. The nature of competition manifested in the coutumiers was a little different. The coutumiers aimed to theorize, regularize, and professionalize the secular courts in the face of ecclesiastical courts, which had already gone through the same process and offered a competing forum at a time when boundaries were still being defined.