Medieval Geopolitics: A Full-Fledged Theory of Medieval Papal Power

By Andrew Latham

In my last column, I discussed the preliminary interpretation of Laurentius Hispanus, in which he justified absolute papal power through the lens of positive law. In this column, I further trace the development of the theory of papal absolutism by analyzing the views of Henricus of Segusio, or Hostiensis as he came to be known after he was created cardinal bishop of Ostia in 1262.

Hostiensis developed the concept of plenitudo potestatis more fully than any of his canonnist predecessors. Through commentaries on Innocent III’s Quanto Personam, and on subsequent Innocentian decretals such as Cum ex illo, Inter corporalia, Proposuit, Magnae devotionis and Cum ad monasterium (in all of which Innocent applied the core concepts first articulated in Quanto Personam to different legal cases) he introduced a number of conceptual innovations that brought the seeds planted by Innocent to full flower.


Basically, Hostiensis refined and amplified Innocent’s idea of vicarius Christi – vicar of Christ. The decretists and early decretalists had not made much of this idea, focusing their attentions instead on the idea of pro ratione voluntas. But in Hositiensis’ hands the idea that the pope shared in and exercised Christ’s divine authority became the cornerstone of a papal absolutism more unfettered than even Tancred of Bologna had espoused. His argument was simple, even if typically expressed in extravagant language. All political authority is derived from God, therefore all who exercise such authority can be said to govern by divine mandate.  But the pope’s authority, he argued, was qualitatively different from that of other princes.  Echoing language used by Innocent and drawing on many of the same texts as Laurentius, Hostiensis argued that the pope did not govern by divine mandate; rather he governed as a divine agent.  As the vicar of Christ he acted in Christ’s place.  Therefore, he concluded in his gloss on Quanto Personam, whenever the pope acts de iure, he exercises Christ’s divine authority and therefore his acts are, ipso facto, licit.  The only factor limiting the papal exercise of this divine authority was sin:  Given that Christ was without sin, Hostiensis argued, the pope simply could not be acting in Christ’s place if he was acting sinfully.

Inscription at front of Archbasilica of Saint John Lateran, cathedral church of the Bishop of Rome: Sacros(ancta) Lateran(ensis) eccles(ia) omnium urbis et orbis ecclesiarum mater et caput meaning “Most Holy Lateran Church, of all the churches in the city and the world, the Mother and Head” – Photo: Marie-Lan Nguyen / Wikimedia Commons

Upon this understanding of vicarius Christi, Hostiensis then proceeded to develop precise legal concepts to replace Innocent’s somewhat woolly formulations.  Perhaps most importantly, where Innocent had written vaguely about papal plenitudo potestatis, and where the decretists had attempted to flesh out Innocent’s thought in rhetorically expansive but conceptually imprecise ways, Hostiensis set out to enumerate the specific legal powers inherent in the pope’s fullness of power.  One way he did this was to attempt to parse the vague phrase ‘above the law’ (supra ius or supra omnia iura) that had come into increasingly wide use among the canonists since Innocent’s decretal Proposuit.  According to Hostiensis, the pope could act supra ius in two ways. On the one hand, under the doctrine of what he (following Innocent) called suppletio defectuum, the pope could make good any deficiency in fact, law or legal procedure. As Watt put it, the suppletio was an act of the absolute power to remedy defects that had arisen either through the non-observance of existing law or because existing law was inadequate to meet the particular circumstances.’ On the other hand, Hostiensis argued that the power to act supra ius entailed the authority to dispense from the law.  Again quoting Watt, dispensation ‘was a use of the absolute power to set aside existing law.’ To be sure, Hostiensis believed that the pope required a valid cause or reason to act supra ius. But he also believed that ultimately it was the pope himself who had the power to determine whether such cause or reason existed in any given case.


Hostiensis also sought to refine the concept of plenitudo potestatis by bringing greater precision to Innocent’s somewhat fuzzy concept of papal ‘divine power.’ He did so by drawing on the works of early thirteenth century theologians such as Godfrey of Poitiers, William of Auxerre and Alexander of Hales, all of whom had distinguished between two facets of God’s divine power: His absolute power (potestas absoluta) and His ordinary power (potestas ordinata).  According to these theologians, potestas absoluta referred to God’s abstract or theoretical power to do whatever he pleased, while potestas ordinata referred to the limited or ordered power He actually chose to exercise. Applying these theological concepts to the idea of papal authority introduced by Innocent in Quanto Personam, Hostiensis argued that the pope, too, exercised two kinds of power. Here, however, he dramatically altered the meaning of the distinction introduced by the theologians. Where they had understood this distinction as referring to the difference between ‘what God could have done other than things he chose to do,’ Hostiensis understood the pope’s absolute power or potestas absoluta as a form of divine power. On his view, the pope’s ordinary power or potestas ordinata was his human power to act within, and on the basis of, the law, while his potestas absoluta was his divine power to transcend the law – that is, his power to act beyond the laws that defined and limited his potestas ordinata.

Drawing these two strands of thought together, Hostiensis further elaborated his idea of potestas absoluta in his commentaries on two other papal decretals, Alexander III’s Ex publico (dealing with marriage law) and Innocent III’s Cum ad monasterium (dealing with solemn vows).  In the first of these, Hostiensis argued that the pope could ‘allow a spouse to separate from an unwilling partner by exercising his absolute power.’ In the second, he made the case that the pope could use his potestas absoluta to dispense from the monastic rule, but only with just cause. Taken together, these commentaries reveal that Hostiensis had come to believe that while the pope could not promulgate divine law, and was in fact subject to it, he could dispense from it in certain narrowly prescribed matters.  This was a new element of papal potestas absoluta.

Hostiensis’ decretist and even decrelalist predecessors had argued that the pope could, in certain circumstances, supplement or dispense from positive law, but none had gone so far as to claim that the pope could dispense from higher law. But Hostiensis now claimed that as vicar of Christ the pope could also exercise God’s authority to set aside natural and divine law as it pertained to marriage and vows. In subsequent comments on Celestine III’s decretal Sicut unire (dealing with the pope’s power to unite episcopal sees), Hostiensis went even farther, arguing that the power to dispense from divine law was not limited to marriage and vows, but could also be used to regulate the status ecclesiae itself. In so doing, he broke with his predecessors who had argued that the pope was bound by the Church’s fundamental constitution and could neither alter nor abolish the status ecclesiae.

But if Hostiensis broke with his predecessors regarding the specific limits of the papal potesta absoluta, he did not break with them regarding the general principle that papal power was in fact limited. For Hostiensis, the concept of plenitudo potestatis did not entail or imply unbridled or arbitrary power. To be sure, as Innocent had argued in his decretal Proposuit, Hostiensis believed that the pope’s potesta absoluta allowed him to act supra ius with respect to positive law simply on the basis of his will.  But even Hostiensis accepted that the pope could only act above natural or divine law ‘with cause’, arguing that the pope could only act supra ius if it was necessary for the public good.  As he put it in his commentary on Innocent III’s decretal Magnae devotionis:


If cause is not present, or is not sufficient, it is not proper for [the pope] to deviate from the law.

And like other jurists of the era, Hostiensis also believed that, although not bound by the law, the pope should nevertheless subject himself to it, except on rare occasions.

16th century printed book of Hostiensis’ writings

A complete genealogy of the late medieval/early modern idea of sovereignty would entail tracing the evolution of all of its constituent concepts (iurisdictio; legibus solutus; plenitudo potestatis; potesta absoluta; pro ratione voluntas; persona ficta; and dominium) across a number of distinct sites of political theorizing (canon law; Roman law; various polemical literatures; and the works of theologians and philosophers) over the course of several centuries (1075-1576).  It would also entail tracing the evolution of the ultimately pervasive belief that the heart of supreme authority to command, legislate and judge was properly vested in kingdoms and other principalities that recognized no superior across those same sites and over the same span of centuries.


Finally, it would entail tracing the evolution of the idea that the source of supreme political authority some sort of synthesis of ‘the people’ and God. In this brief essay, however, my goal was somewhat less ambitious: to demonstrate the plausibility of such a genealogy by tracing the evolution of three key constituent concepts of sovereignty (plenitudo potestatis; potesta absoluta; and pro ratione voluntas) at one particular site of theorizing (canon law) during one specific century (the thirteenth). The argument I developed was that, in Quanto Personam, related decretals, and their glosses, Innocent and the canonists made a number of important contributions to the idea of supreme authority – ideas that would eventually be picked up by early modern thinkers like Jean Bodin and worked into their theories of sovereignty. The pope established that the papal office was the sole locus of supreme authority within the Church and that, as vicar of Christ, the pope alone exercised what he called ‘divine power’ on earth.

Building on this, the canonists began reimagining the legal character of papal authority, first by locating the source of canon law in the will of the pope and then by loosing the pope from almost all of the constraints of positive, natural and divine law (at least in certain circumstances). In the process, they developed and refined a number of concepts – pro ratione voluntas; plenitudo potestatis; potesta absoluta – that in subsequent centuries were to be transferred from the pope as the ruler of the Church to temporal rulers of kingdoms and other principalities.

Andrew Latham is a professor of political science at Macalester College in Saint Paul, Minnesota. He is the author, most recently, of The Idea of Sovereignty At the Turn of the 14th Century. You can visit Andrew’s website at or follow Andrew on Twitter @aalatham 

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Top Image: The coronation of a pope – British Library MS Harley 4379   f. 34