The relationship between Louis IX of France and the mendicant orders is well known. Yet it has generally been studied in order to shed light on Louis' reign rather than on the development of the orders. Contemporaries tended to criticize friars who worked too closely with secular authorities and their suspicions have passed into the historiography. This means that we know less than we might about how friars created and used opportunities to carry out their mission in the wider world. This article considers how Louis and members of the religious orders worked together during his crusade of 1248–54 to bring about the conversion to Christianity of Muslims and Mongols. It looks at the ways in which they drew on ideas of the apostolic life and wider papal agendas, but also employed standard strategies of diplomacy and debate, seizing on a range of opportunities as they arose. A second strand investigates their experiences in the light of scholarship on the Mediterranean and of more global cultural encounters. How far did their time in the Mediterranean and beyond influence the way that they thought about the world and their own faith?
