A wide array of diplomatic texts, including contracts, peace treaties, donations, oaths of fealty and other types of documents that carried legal force were exchanged among the different western-led groups operating in the Latin East from the twelfth century onwards. Although the bulk of these texts were written in Latin, a suprisingly large number were written in French only, with a smaller percentage written both in Latin and in French. These texts, which survive in cartularies and document collections throughout Europe and the East, are witness to the substantial role played by the French language in the the legal and administrative functioning of the following organizations:
Peter Edbury, “Crusader Sources from the Near East (1099-1204),” in Byzantines and Crusaders in Non-Greek Sources, 1025-1204. Edited by Mary Whitby. Oxford: University Press, 2008, 23-38.
Diplomatics in the Eastern Mediterranean 1000-1500. Edited by Alexander D. Beihammer, Maria G. Parani and Christopher D. Schable. Leiden: Brill, 2008.
For a collection of previously unedited diplomatic texts, see:
La présence latine en Orient au Moyen Âge. Edited by Ghislain Brunel and Marie-Adélaïde Nielen, with Introduction by Marie-Paule Arnauld. Paris : Centre Historique des Archives de France, 2001.