This volume collects essays from an international group of scholars who treat various aspects of the Fourth Lateran Council's placement within the development of the 'ius commune'. Topics include the canon law about armsbearing clergy, episcopal elections, heresy, degrees of affinity within marriage, the oversight of relic veneration; two essays highlight the council's reaction to the Fourth Crusade's sack of Constantinople in trying to incorporate the eastern church into the ecclesiastical structure and liturgical norms of the Roman Church; several essays concentrate on the usage of Roman or civil law in some of Lateran IV's constitutions and emphasize issues of private and procedural law. Collectively, and headed by an essay by Anne J. Duggan on the relationship of Pope Alexander III's pontificate to the Lateran IV constitutions, the essays create a fuller picture of Innocent III and his curia's reliance on developments within the jurisprudence of the preceding half century, but they also reveal the ways in which they forged new paths and made significant contributions to guide canon law in the years following the council.