This essay provides an account of the uncomfortable discrepancies in the way Muslim conversion is depicted among the early Latin histories of the First Crusade. Local contexts within western Europe shaped fundamentally different views of the Crusades. An author writing from within the context of his experiences in the Norman world of southern Italy understood interactions between Christians and Muslims far differently from his contemporaries in northern France. This is a world in which the lines between Islam and Christianity were more fluid than we would at first expect. While the southern Italian Gesta Francorum depicts Muslim conversion at Antioch in terms of an alliance between Christian and Muslim warriors, subsequent Latin histories minimize such cooperation, bringing the account of the siege into the more readily accepted polarized view of the relation between Islam and Christianity that continues to haunt the history of the Crusades down to present day.