The subject of this legal historical investigation is the legal relationship between the shipmaster and his crew, as outlined in the Rôles d'Oléron, the most significant French source of maritime law, and the Llibre del Consolat de Mar, the most important Catalan source of maritime law. The individual chapters will first conduct a separate examination of both sources, followed by a comparison between them. The background is the assumption that the Llibre del Consolat de Mar was influenced by the famous Rôles d'Oléron.