Concentrating as he did on the office of adelphopoiesis preserved in Eastern Christian liturgical sources, John Boswell gave short shrift to the West. Although he believed that the ritual was known and practiced there, the only documentary trace of any similar ceremony he discussed was an account that Gerald of Wales included toward the end of the twelfth century in his Topographica Hibernica. Boswell did present a fifteenth-century French pact of brotherhood in translation in an appendix, but he did not consider its ceremonial significance in his text. Nor did he believe it pertinent to his topic, labeling it as he did, “an agreement of ‘brotherhood',” and terming it “[a] treaty of political union using fraternal language.” I shall discuss Gerald's account and this compact later, in the course of analyzing a variety of evidence regarding ritual brotherhood in Western Europe between the eleventh and fifteenth centuries. I shall attempt to show that ties of brotherhood contracted formally and ritually between two individuals were more common in the West than Boswell believed. I shall argue that bonds of ritual brotherhood similar to those solemnized in the office of adelphopoiesis existed in many parts of Western Europe in the later Middle Ages, in areas far removed from the regions of Italy subject to Byzantine influence, where euchologies containing the Eastern ceremony were preserved.’ In dealing with the Western evidence I shall be particularly concerned with its nature, which contrasts strikingly with the Eastern sources. For the East, the most abundant documentation is liturgical, and traces of such relationships in other sources are rare — although (as Claudia Rapp shows in this symposium) not as sparse as has sometimes been thought. For the West the situation is precisely the reverse.’ The Western cases of individuals linked by ritual fraternal ties that Du Cange presented far outnumber the Eastern instances he cited, and additional Western examples have come to light since his time. However, as regards the ceremonial by which the ties were forged in the West, there is no strictly liturgical evidence. Western liturgical books contain no special prayers and offices for making brothers. Narrative and documentary sources cast fitful light on the nature of the ceremony that accompanied the unions, but they do not suggest that any uniform ritual ever existed. Why this was so is a matter for speculation, but I believe that the absence of fraternal ceremonial from the liturgy is closely related to another distinctive aspect of the institution in the West: the lack of prohibitions, ecclesiastical and secular, against the bond. I shall consider this issue after examining the various motives that seem to have underlain the Western fraternal alliances, and also the outcomes of the unions. In the end I shall propose that whatever the differences in documentation, and despite the difference in the ritual practices, striking formal and functional likenesses existed between the Eastern and Western institutions of ritual brotherhood linking two participants: in the purposes they served, the means by which they were contracted, and the gap that often existed between ideal and reality. In a final section I shall discuss the problems associated with attempting to establish whether or not — or when and how often — Western (or Eastern) rituals of brotherhood formalized relationships that involved or were expected to involve sexual intercourse between the participants.