Libellus de imperatoria potestate in urbe Roma
Libellus de imperatoria potestate in urbe Roma is an anonymous Latin treatise on "imperial power in the city of Rome". It has been dated as early as the late 9th century and as late as c. 950, and was probably written at Spoleto. It survives in one mansucript, appended to the contemporary Chronicon by Benedict of Sant'Andrea.
The Libellus argues for the authority of the Holy Roman Emperor in the so-called "patrimony of Saint Peter". Ferdinand Gregorovius calls its author an "Imperialist" and a "partisan", and doubts the accuracy of his claim that "[the emperor's] legate resides in Rome at all times". According to Eleanor Duckett, the author of the Libellus "poured out his feelings into that interesting document". The author clearly sides with the Emperor Louis II against Pope Nicholas I.
- Giuseppe Zucchetti, ed. Il Chronicon di Benedetto, monaco di S. Andrea del Soratte e il "Libellus de imperatoria potestate in urbe Roma", Fonti per la storia d'Italia, 55. Rome: 1920.
- Georg Pertz, ed. "De imperatoria potestate in urbe Roma libellus", Mon. Germ. Hist. Scriptores, iii, 719–22.
- Ferdinand Hirsch, "Die Schenkung Kaiser Karls des Kahlen für Papst Johann VIII und der Libellus de imperatoria potestate in urbe Roma", Forschungen sur deutschen Geschichte, 20.
- Marios Costambeys, Power and Patronage in the Early Medieval Italy: Local Society, Italian Politics, and the Abbey of Farfa, c.700–900. Cambridge: Cambridge University Press, 2007.
- Karl Josef Heidecker, The Divorce of Lothar II: Christian Marriage and Political Power in the Carolingian World (Cornell University Press, 2010), 41 n.18.
- Benedict's Chronicon stresses the dominance of Dukes Alberic I and Alberic II of Spoleto during the papacy of John X and John XI, even incorrectly labelling the dukes imperial viceroys, cf. John Howe, Church Reform and Social Change in Eleventh-Century Italy: Dominic of Sora and His Patrons (Philadelphia: University of Pennsylvania Press, 1997), 25 n.4.
- Johannes Fried, Donation of Constantine and Constitutum Constantini: The Misinterpretation of a Fiction and its Original Meaning (Walter de Gruyter, 2007), 46. For the constitutional basis of this authority, cf. Pactum Hludowicianum.
- Inventum est, ut omnes majores Romae essent imperialies homines, et ut suus missus omni tempore moraretur Romae ("It is found that all the great men of Rome are imperial men, and therefore his [the emperor's] legate all the time resides in Rome"), quoted in Gregorovius, The History of the City of Rome in the Middle Ages (Rome: 1905), V, 8.
- Duckett, Death and Life in the Tenth Century (Ann Arbor: University of Michigan Press, 1968), 138.