In the last fifty years or so, the history of medieval Christianity has cast its gaze beyond the well-known figures – the popes and bishops, emperors and kings, saints and monks – who shaped the older narratives and expressed the era’s most enduring ideals. Historians now routinely consider the lowly rural priest, the industrious nun, and the masses of lay people who formed the populus Christi of the chronicles. The shift in perspective does more than simply expand the picture: it allows us to recognise the roles played by individuals and communities labouring in the margins of church institutions and conventional society. This essay examines a diverse but important group of people who defy easy categorisation yet were all loosely associated with religious life. As hermits and recluses, lay ‘penitents’, beguines and beghards, their status was ambiguous, straddling the border between the lay and monastic (or religious) categories of society. Although they identified themselves as orthodox Christians and were indeed often praised as supremely devout, they tended to resist incorporation into the formal structures of religious life and left little trace in official records until about 1100. In the period covered by this volume, however, their numbers, influence and public prominence increased widely.