The Catalogus Baronum is a compilation of registers concerning the military obligations owed by the barons of the Kingdom of Sicily. The surviving collection was compiled in 1322 under the Angevin dynasty. It contains three distinct registers from different periods and covering different regions of the kingdom. Although often treated primarily as a feudal or military register, the Catalogus is also a fundamental source for the study of lordship, county organization, and royal administration in the mainland provinces of the kingdom. James Hill has re-examined the text chiefly in relation to recruitment and the administration of the armies of the Norman kingdom, while Hervin Fernández-Aceves has emphasized its value for reconstructing lordship, county reorganization, aristocratic agency, and royal administration in the mainland provinces.