This project relies on an interdisciplinary and collaborative approach to investigate how and to what extent three factors determined the perceived identity and real-life experiences of religious communities in the early and high medieval West: (a) rules and other normative products of written culture that were transmitted from one generation to the next, (b) local variables and contingencies that impacted on the composition, development, and societal embedding of religious communities, and (c) various forms of entanglement and cross-fertilization with other religious communities and movements. By relying on a bottom-up perspective on community building and considering a wide range of written typologies and contexts, the research aims to submit decisive evidence in support of a drastically more nuanced understanding of the religious landscape in the tenth to thirteenth centuries compared to the one that currently dominates scholarly discussions.