Scholarship of the late nineteenth and early twentieth century – not least that cultivated by members of the Plainsong and Medieval Music Society and other scholarly groups – regularly sought to define the means through which liturgy moved between Continental Europe and Britain and Ireland. In the later twentieth century, a concept of cross-cultural exchange became more prominent: this model emphasised how people shared knowledge and ideas as they travelled between different religious centres. As the first set of case studies has shown, the presence of Sarum and York liturgy across the greater part of Britain and Ireland offered a certain consistency, but the reality was certainly much more subtle and complex, with no two textual witnesses supporting a picture of uniformity even between institutions connected by geography or other factors. Instead, the picture that emerges is more of a patchwork of regions and networks, within which there might be a striking diversity of related customs.