This work investigates the evolution of political theory and the concept of kingship during the Carolingian period. Walter Ullmann, a distinguished medievalist, examines how the Carolingian rulers utilized theological and legal frameworks to legitimize their authority. By analyzing primary sources and historical records, the author argues that the Carolingian era served as a critical bridge in the development of Western political thought, specifically regarding the relationship between the church and the state.

Scholars recognize this text as a foundational analysis of medieval political ideology and the intellectual history of the Carolingian period. Readers frequently note the academic density of the prose, which requires a strong background in medieval history to fully appreciate the author's arguments.