This chapter analyses the complex social position of the duke of Brittany as presented in the legal arguments for Jeanne’s succession in 1341, a document which has been completely overlooked by modern historians. It argues that the debate centred around the ambiguity of the ducal rank: did the duke legally have more in common with the nobles of Brittany than with the kings of France? In this framework there were two communities (to use the modern terminology) or bodies politic (the medieval) to which the duke could conceivably belong and where their primary responsibilities lay. While this was a learned view constructed for immediate advantage, the case reflected wider contemporary difficulties with parsing the internal stratification of the nobility and the inherent tension within the ducal role as a subordinate sovereign. These challenges were exacerbated because standards of divided succession influenced contemporary interpretations of status, overlaying questions of shared lordship over the different hierarchical layers. The blurring of these lines challenges the historiographical prioritization of the competitive centralization of power through the strict demarcation of ruler and ruled in the later Middle Ages.