This dissertation examines inventiones, that is narratives of relic discoveries, written in southern Italy between the tenth and twelfth centuries. During this period, communities dealt with sweeping changes brought on by political upheaval, invasion, and ecclesiastical reforms. Several inventiones written concomitantly to these events have received little scholarly attention. This dissertation has two goals: to enhance our understanding of the genre in general and to explore further the local circumstances that prompted their composition and copying. The following four case studies pertain to Christian communities in Naples, Benevento, and Larino, and the abbey of San Vincenzo al Volturno respectively. This dissertation argues that, because of their "inventive" nature, these sources were powerful means of writing and rewriting history and, more often than not, the exercise of historical memory fueled their production. In particular, this dissertation contends that in eleventh-and twelfth-century southern Italy, as communities underwent the transition from Lombard to Norman authorities, the memory of the Lombard lords of the past was utilized in inventiones as a powerful tool to rewrite the identity of a community as it negotiated the changing political and ecclesiastical landscape. Furthermore, this dissertation argues that because of the devotional nature of inventiones, typically composed for use in the liturgy and thus potentially exposed to a large public, the history encoded within these sources was made all the more powerful. Inventiones reveal how the liturgy, ritual, and devotion were mobilized by medieval communities and display an inherent reciprocity between historical and devotional writing and thought. In order to unlock these features as well as the local conflicts and agendas that prompted the production of inventiones, both a close study of the original manuscripts of extant inventiones as well as attention to contemporary liturgical, diplomatic, and material sources are major components of each case study.