THIS BOOK EXPLORES how aristocratic leadership was understood in response to the political conflicts of the late Middle Ages. It focuses on how elite audiences engaged with different ideas about men's and women's joint authority as a way to make sense of these clashes. Tracing the development of this discourse in a case study across the fourteenth to sixteenth centuries, I argue that the tensions defining political society encouraged a perpetual reassessment of the dynamics of legitimate power, which became comparative rather than categorical.

The protagonists, so to speak, of this analysis are Charles de Blois (ca. 1321–1364) and Jeanne de Penthievre (ca. 1326–1384), duke and duchess of Brittany in what is now northwestern France. Jeanne was the niece of the previous duke, Jean III, while her husband Charles was the nephew of the king of France, Philippe VI. Jeanne was expected to succeed her childless uncle to the Breton title in 1341, but her half-uncle Jean de Montfort challenged her claim. Despite winning the legal confirmation of her rights from the king's parlement at Paris, the support of King Edward III of England for her rival led to war. Jeanne and Charles controlled much of the duchy for over two decades, but their authority faced repeated disruptions, including several major military defeats, Charles's capture and nine-year imprisonment in England, and the surrender of two sons and one daughter as hostages for his ransom. The conflict abated only after Charles died at the battle of Auray in 1364 and Jeanne signed a treaty recognizing Jean de Montfort's son as Duke Jean IV in 1365. Nevertheless, she remained titular duchess and pursued an active political career for the rest of her life.

I am not concerned here, however, with the events or even the rhetoric of Jeanne and Charles's actual exercise of power, which I have analyzed primarily from Jeanne's perspective elsewhere. Instead, I am interested in what other people had to say about their authority after the fact.