My dissertation focuses on interactions between tenth-century bishops and religious communities in the church province of Rheims, between c. 888 and 1073. It offers new insight on the history of the early medieval Frankish kingdoms, more specifically, on the concept of monastic reform, the relations between abbeys and bishops, the post-Carolingian political transformation and the mechanisms of lordship. The main goal of this research can be summed up in three questions. First, what political circumstances and relations levered or limited episcopal agency to intervene in monasteries? Second, how did such intervention impact his lordship? Third, how did bishops try to maintain their influence in the precarious and ever-changing local power balances of tenth-century West-Francia and Lotharingia? The result of this research is a fundamentally new approach to these bishops and their relations with religious houses. It encourages scholars to further discard the legalist or institutional perspective, and instead concentrate on the agency of the individuals in this complex interplay between abbots, lay princes and bishops.