Apropos of Spanish or Languedocien elements manifest in the late 13th-century Durandus Pontifical, this study explores the relationship between high medieval ritual and identity formation. It introduces the notion of liturgical use, an inclusive term for the body of customs that determined the way ceremonies were performed by lasting communities with a sense of belonging together. The primary challenge of comparing uses lies in selecting and systematizing the relevant information and interpreting the results. The authors argue that this challenge can be met by reducing the evidence to textual items and positions that lend themselves to large-scale comparative analysis in both time and space. As the main methodological contribution, they introduce the principle of mapping and drawing historical and cultural conclusions from their patterns. By summarizing a decade of careful research into thousands of sources accomplished by the team of the Usuarium database, they present four historical layers of medieval liturgical history, termed formative periods, and outline convergent geographical areas that they call liturgical landscapes. Since data on a lower level rarely correspond to smaller contiguous areas, they interpret the phenomenon called artificial diversity through medieval concepts of regionality and cultural transfer, formulating some thought experiments to understand the ways in which a Europe of uses once functioned.