Nithard’s Histories, a remarkable first-hand account of how the Carolingian Empire built by Charlemagne was ripped asunder by his feuding grandsons, provides more than simply a lens through which to view the events relevant to the political maelstrom battering the Carolingian world in the 840s. The work’s basic structure, particular language, and principal concepts reveal a coherent, consistent, and poignant worldview and offer modern scholars a window into the values and perspectives common to the mid-ninth century. This article concentrates on Nithard’s analytical tools and brings into sharp focus the work’s deep continuity, its internal reasoning, its sophistication, and its audience. Nithard analyzed his world as working according to a sacramental logic and identified lapses in fidelity as the fundamental problem. Basic Christian catechetical ideas profoundly inform Nithard’s analysis. The basic consistency of his sacramental logic combined with omnipresent religious concepts illumines a broader elite discourse common to the mid-ninth century.