The political significance of Eleanor and Marguerite of Provence's marriages to Henry III of England and Louis IX of France, respectively, is well known. Equally, it is generally accepted that the surviving correspondence exchanged between the English and French royal families illustrates both the intimate relationship that developed between them in the decades following these marriages, and the exceptional cooperation between the two kingdoms resulting from this intimate relationship. The details of the correspondence, however, are less known, particularly of the letters written in Eleanor and Marguerite's names. The present essay considers some of these exchanges, focusing on those written during the Second Barons’ War in the 1260s, together with those written during the Provençal inheritance dispute in the 1280s. Through an examination and comparison of these letters, this essay will expound the relationship between language of politics and family, with particular attention to how ‘family’ was used as a conceptual and rhetorical tool for persuasion within thirteenth-century Anglo-French language of politics by members of both the Angevin and Capetian royal families. In doing so, this essay also re-evaluates basic assumptions about the representation and practice of female power, authority, and diplomacy in the thirteenth century.

First, letters. By royal letters, I mean those letters that were written in the names of members of the royal family, were intended for communication between the sender and the receiver, and were concerned with administrative, familial, and/or political matters – but had no juridical force. These letters were always written by scribes or secretaries, who often also translated the agreed-upon message from the vernacular into Latin. Because members of the royal family frequently corresponded with fellow rulers who were also kindred, and because royal letters were fundamental tools in both governing and nurturing relationships between medieval rulers, royal letters necessarily combined the personal with the political. Yet, while the contents of royal letters have been used as sources to contribute to both biographical and historical narratives, the letters and exchanges themselves – their form, formalities, and diplomatic – have been somewhat overlooked. This is due to assumptions that the irretrievable oral messages that generally accompanied letters contained the most important information, while the written message was a mere pretext.