So far, traditional scholarship on medieval penitence has mostly analysed it through the lens of a perceived ‘dichotomy’, namely, in the way it was interpreted by medieval people either as a set of external practices (confession and penance), or as an internalised emotional process (contrition). However, this approach kept the focus away from the practical impact that a ‘contritionist’ interpretation of confession, mostly developed in monasteries, would have had on the widespread practice of clerical lay Christians alike. The penitent’s requirement to experience an emotional, heartfelt repentance, but also generally to feel ‘rightly’ in order to be eligible for God’s forgiveness granted in confession, can indeed raise many questions regarding its pastoral practicality, especially in the wake of Lateran IV’s imposition of compulsory yearly confession for all Christians. In this thesis, I examine the place and role of emotionality in the practice of confession. Specifically, I focus on how scholars, pastors and penitents navigated the many tensions and difficulties posed by affective considerations in confession around the time of Lateran IV, more specifically, the perception of emotions as ‘spiritual instruments’. This will reveal further critical insights about medieval mentalités. Methodologically, this will be carried out firstly by examining twelfth-century scholastic writings on penitential emotions, which helped developed the confessional doctrine of Lateran IV; secondly, by studying Latin pastoral sources, such as confessors’ manuals and compilations of exempla, in order to evaluate the application and interpretation, in confession, of the emotional teachings developed by scholastics; lastly, by using vernacular literature in order to determine how and in which terms the laity assimilated such emotionality in their practice of confession. I demonstrate that pastors could be very flexible in interpreting this penitential emotionality, by adapting emotional demands to the penitents and increasing the role of the confessor in the development of the penitent’s penitential affectivity. This not only facilitated access to successful confession for the average Christian, but also allowed the expression of a lay affectivity in relation to God and sins, thus facilitating the development of new ways for the laity to formulate and internalise Christian beliefs.