Friendship - a voluntary emotional and social affiliation of two persons outside of, or in addition to, the structures of kinship and marriage - is often thought of as a relationship particularly pertaining to same-sex interactions. This thesis focuses on medieval english and french Arthuriana, and argues that friendship between men and women was sufficiently well understood as to be woven into the imaginative stock of medieval romance. Such friendships are by no means the dominant relationship type between men and women, but they are tightly linked with the power structures of marriage, family and lordship. This thesis uses adaptation and translation studies methods to approach translated works as responses to the ethical and affective dimensions of the adapted text, with particular attention to the role of fiction as a source of emotional ‘scripts' for communities of readers and audiences. Where adapted texts pay particular attention to, or take pains to limit, friendships between men and women, these points of change provide access to particular ethical, emotional and social considerations available to the audience of the adapted text. Case studies addressed include The Romaunt of the Rose, Ywain and Gawain, the Morte Arthur narratives, and the Prose Merlin.