The boundaries between sacred and secular in the late Middle Ages, traditionally perceived as separate domains, are nowadays perceived as porous or non-existent. This collection on religious connectivity explores a new approach to religious culture in the late Middle Ages. In assessing the porosity of the domains of sacred and secular, and of religious and lay, the contributors to this collection investigate processes of transfer of religious knowledge, literature, and artefacts, and the people involved. Religious connectivity describes people in networks. This concept emphasises dynamics and processes rather than stability, and focuses on all persons involved in transfer and appropriation, not just the producers. It is therefore a fruitful concept by which to explore medieval society and the continuum of sacred and secular. By using the lens of religious connectivity, the authors of this collection shed new light on religious activities and religious culture in late medieval urban communities.