Historiographical Introduction

Traditionally, many histories discussing the papacy in the central Middle Ages (1000–1300) described the growth of “papal monarchy” and struggle between Church and state as defining features of Latin Christendom or Western civilization. Typically, scholars attributed the zenith of the usage and redefinition of the title “Vicar of Christ” and the extent of powers implied in it as occurring between the pontificates of Innocent III (r. 1198–1216) and Boniface VIII (r. 1294–1303), until the papal powers implied by that title were challenged and checked by growing monarchies, papal schism, heresies, the calamities of the fourteenth century, conciliarism, and, finally, the growth of the Renaissance, the Protestant Reformation, the Enlightenment, and the Age of Revolution.Footnote ¹

Discussion of the term “Vicar of Christ” is therefore typically situated within a historiography of the papacy which presents popes as “monarchs” intent on developing bureaucracies, revenues, and functions as the court of last appeal in competition with secular rulers, leading to “inevitable” contention. For Walter Ullmann in particular, the papacy had to assert its position as absolute head of the Church and superiority over the emperor as ultimate ruler of Christendom; papal power was defined in relation to secular power and in relation to bishops, regional churches, cardinals, and councils, with whom popes had to collaborate and negotiate while attempting to assert ultimate authority as supreme leader of the Church. As “Vicar of Christ,” popes could claim to be supreme judge and arbiter of the entire world. The portrayal of popes as monarchic, mandating, and hegemonic suited the attempts of legal, political, and constitutional historians to depict the growth of royal power, legal systems, centralization, taxation, bureaucracy, and “nations,” in competition with forms of dissent, the growth of representative bodies, and other forms of identity (such as Latin Christendom).Footnote ²

This formerly prevalent model has been challenged by recent characterization of the medieval papacy as responsive and dialogic rather than mandating and hegemonic. In other words, popes responded to petitions and requests sent by secular rulers, individuals, and regional churches to Rome because papal authority was seen as useful for solving particular kinds of problems. Similarly, the extent and applicability of papal claims to authority in worldly and spiritual affairs were endlessly renegotiated with others also claiming authority and jurisdiction. Individual popes’ claims to combine religious authority and worldly dominion simply meant they “simultaneously inhabited multiple roles” as “head of the universal Church, bishop of Rome and ruler of the Papal States.”Footnote ³ Papal registers testify to a continual dialogue between center (Rome) and periphery in terms of appeals and petitions presented to the papal curia for adjudication in matters of canon law, doctrine, praxis, Church government, marriage, crusades, and politics.

Papal opinion and legal rulings mattered precisely because they were sought by regional churches and by secular rulers.Footnote ⁴ Increased papal usage of “Vicar of Christ” coincided with the growth of regional and ecumenical councils. These councils were not merely ceremonial occasions intended to display papal authority through ritual and the imposition of pre-formulated decrees substantially unmodified by the council’s proceedings; they functioned as occasions for information-gathering and dialogic exchange.Footnote ⁵ Despite Innocent III’s presentation of himself as another Christ at Lateran IV (1215), the council’s decrees were imagined as dialogic in preparation and final drafting, petitioners presented cases, and rulings on contested instances of secular succession and inheritance were hotly debated by representatives of all parties concerned.Footnote ⁶ Even when councils were not in session, popes relied heavily on the College of Cardinals, judges delegate, and papal legates as “vicars” working in various regions to represent papal decision-making.Footnote ⁷

Moreover, the specific contexts in which popes employed and reinterpreted the title “Vicar of Christ” must be considered. When writing to parties outside Latin Christendom, popes generally invoked the term “Vicar of Christ” less often. In the disputes leading up to the Greco-Latin schism of 1054 and during later negotiations for reunion, because of the hotly contested hierarchy between patriarchates in the wider Christian world (Antioch, Jerusalem, Alexandria, Constantinople, Rome), popes preferred the title “Vicar of St. Peter” to argue for the primacy of Rome and papal fullness of power.Footnote ⁸ However, in papal letters addressed to pagan, Mongol, and Muslim rulers declaring crusade or urging conversion, thirteenth-century popes invoked their role as vicars of St. Peter and Christ to stress their duty to spread the Christian faith.Footnote ⁹

Origins and Early Usage of “Vicar of Christ”

As early popes sought to establish Rome as the “apostolic seat,” they favored the papal title “Vicar of St. Peter” to stress that papal primacy (authority over other bishops and patriarchs) derived from Peter, who had received his vicariate from Christ. Patristic writers invoked biblical authorities such as Matthew 16:18–19, which described the transfer of Christ’s authority to Peter in terms of the keys to the kingdom of heaven and the power to bind and loose (absolve, impose penance, excommunicate) both on earth and in heaven. As Vicar of Christ and Peter, popes exercised on earth the same authority as God. However, this authority was paired with responsibility; Christ had also entrusted the entire Church to Peter to “feed” as supreme pastor (John 21:16–17).Footnote ¹⁰

By the fifth century, papal correspondence wielded the title “Vicar of St. Peter” to claim that the pope’s position as successor to Peter, leader of the apostles, granted him authority over all other Church leaders.Footnote ¹¹ Leo I (r. 440–61) and Gelasius I (r. 492–96) argued that, as vicars of St. Peter (who was Vicar of Christ), popes exercised jurisdiction as Christ’s representatives (vices), although the term “Vicar of Christ” was also routinely wielded by bishops and priests in a spiritual sense and by Eastern and Western emperors to claim that they exercised Christ’s temporal authority on earth.Footnote ¹² However, the title “Vicar of Christ” was invariably linked to the more prevalent title “Vicar of Peter”; both were employed to assert papal primacy over Western bishops and papal authority in letters to Eastern Churches and rulers. However, ecclesiastical writers often averred that secular rulers (including Eastern emperors and Carolingian rulers) also served as Vicars of Christ or God on earth.Footnote ¹³ The weaponization of the term “Vicar of Christ” would occur only much later, during the eleventh-century reform movement.

The Eleventh-Century Reform Movement

Historians have often either hailed or decried the “Gregorian” or eleventh-century reform era as laying the groundwork for the expansion of ecclesiastical jurisdiction and bureaucracy in the later twelfth and thirteenth centuries – the era of “papal monarchy.”Footnote ¹⁴ In fact, the eleventh century was characterized by increased contact between the papal curia and rulers and bishops throughout Latin Christendom, and by the forging and communication of papal concepts of authority before various audiences with whom popes both collaborated and conflicted.Footnote ¹⁵ The highly varied reform movements of the long eleventh century often included measures intended to “free” the institutional Church from lay concerns and influence. Political posturing accompanied “mutually catalytic” reimagining of the Church’s organization and hierarchy in grassroots religious movements, polemical treatises, letters, and canon law collections.Footnote ¹⁶ The end result, although not inevitable, was a Church reconceived with the pope as supreme ruler in both spiritual and temporal matters.

The growth of canon law and theology that accompanied the reforms of the eleventh and twelfth centuries provided key contexts for defining the attributes assigned to the title “Vicar of Christ,” which eventually eclipsed that of “Vicar of Saint Peter.” Both terms played key roles during the Investiture Conflict, which originated over the question of who (cathedral chapters, popes, temporal rulers) should control episcopal elections and invest episcopal appointees with the tokens (crozier, miter, ring) of their spiritual power as “Vicars of Christ” and of the lands and temporal duties attached to their office. Although historians have highlighted the polemical battles between popes and German kings, both prior to and during this period the government of the Church was divided between temporal and spiritual “vicars.” Bishops exercised secular authority while kings were anointed with holy oil and the German emperors Henry III (1046–56) and Henry IV (1056–1106) had intervened in papal elections in order to support Church reform efforts. Gregory VII’s declaration that all Christian government, secular and sacred, was subject to the absolute authority of the pope irked not only German kings but some reformers, including canon lawyers, monasteries, and bishops. Many disagreed with Gregory’s claims to be able to appoint and remove bishops, to depose emperors and release their subjects from oaths of fidelity.Footnote ¹⁷ In the name of reform, multiple popes claimed the supreme exercise of spiritual and temporal authority over all Christendom, leading to a breach with the Greek Church (1054) and the Investiture Conflict.

One of the authoritative texts frequently cited by Gregory VII (1073–85) and his supporters to justify theoretical papal supremacy was the spurious Donation of Constantine. Probably drafted during a period of Franco-papal alliance, the Donation purported to record the Roman emperor Constantine’s gift to Pope Sylvester I (r. 314–35) and his successors of the imperial crown and universal spiritual and worldly sovereignty, as well as the direct temporal rule of the lands which composed the papal states in Italy.Footnote ¹⁸ Although Gregory VII initially justified his excommunication of Henry IV (in 1076) as an exercise of the keys entrusted to the pope as vicar of Peter,Footnote ¹⁹ polemicists including the fiery Peter Damian quickly declared that both Peter and his successors, the popes, were the true Vicars of Christ, in support of papal primacy.Footnote ²⁰ The Dictatus papae (c.1075) made similarly radical claims for universal papal jurisdiction over bishops and secular rulers and papal immunity from judgment.Footnote ²¹ During an intense propaganda war, imperial supporters, many of them bishops, retaliated by invoking the imperial title “Vicar of God” (vicarius Dei) to rationalize the emperor’s authority to intervene in Church matters.Footnote ²² De consecratione pontificum et regum (c.1100–1101) argued that, while bishops were, as vicars of the apostles, indirectly vicars of Christ, the king was Christ’s direct vicar and could legitimately invest bishops with their churches. Gratian’s Decretum and early commentators remained conservative, attributing the title “Vicar of Christ” to priests, sovereigns, and bishops.Footnote ²³

These theoretical positions were staked in response to contemporary religious and political circumstances. Gregory VII’s own views evolved over time, from the traditional division of earthly and spiritual authority implied by the Gelasian theory of the “two swords,” to the position that both “swords” were ultimately wielded by or bestowed by popes as Peter’s successors. Henry IV’s supporters advocated for the separation of powers and the emperor’s direct reception, as Vicar of Christ, of the sword of temporal authority from God; pro-Gregorian theorists claimed that emperors wielded the temporal sword only with papal approval, which could be withdrawn, while Gratian’s Decretum incorporated authorities and arguments for a spectrum of positions.Footnote ²⁴ Ironically, by applying Roman law’s descriptions of the imperial role to the pope’s role as head of the universal Roman Church, Gratian enabled the future equation of papal and imperial power. Just as Roman emperors were not bound by the law, so too none could judge popes, although like Christ, both popes and emperors should obey the law voluntarily. Divine and natural law limited both papal and imperial power; rulers were bound by equity, just cause, and the common good when making or dispensing from the law.Footnote ²⁵

In contrast, pro-papal canon law collections and theological writers turned to the traditional descriptions of Peter as Christ’s vicar to systematically work out the implications of papal authority and primacy implied by that title. In his reforming treatise De consideratione (c.1149–52), dedicated to his former student, then Pope Eugene III (r. 1145–53), the tremendously influential Bernard of Clairvaux promoted the concept that the pope was not merely Peter’s vicar, but Christ’s. He did so to stress that papal authority was universal and superior to that of other bishops and secular rulers and should be exercised to reform the Church, concepts which later deeply influenced Pope Innocent III, who read De consideratione. However, Bernard was uninterested in systematic explications of papal jurisdiction or titular usages. While claiming that both Gelasian swords belonged to Peter’s papal successors, he urged them not to wield the material sword directly but delegate its use to secular authorities.Footnote ²⁶

From Alexander III to Innocent III

Perhaps in response to Bernard’s treatise, both during and after the pontificate of Eugene III, the papal chancery began favoring the term “Vicar of Christ,” particularly under Alexander III (r. 1159–81), who faced a split papal election and an ambitious German emperor: Frederick Barbarossa (1155–90). From roughly 1150 to 1250 CE, a series of conflicts between popes and the Hohenstaufen emperors assumed a more political and legalistic tone than those of the “Gregorian” era. The greater systematization of law in both secular and Church courts meant that lawyers and polemicists tried to define papal spiritual and temporal jurisdiction with greater precision. One particularly thorny issue was imperial claims to sovereignty over Italy and Rome and papal counterclaims that any rights the emperor possessed in those regions were delegated by the pope to a firmly subordinate emperor. Nonetheless, Frederick Barbarossa initially used the term “Vicar of Christ” to support Alexander III.Footnote ²⁷

However, when the English Pope Adrian IV (r. 1154–59) declared that “we, although unworthy, act on Christ’s behalf on earth” to argue that the pope held both Gelasian swords and granted that of imperial authority to the emperor, Frederick Barbarossa countered that, in fact, the emperor was Christ’s vicar and the idea that popes, as Christ’s vicars, granted imperial authority was an “unheard-of innovation” (inaudita novitas).Footnote ²⁸ The “problem” lay in Adrian’s application of the title “Vicar of Christ” to papal supremacy in both the political and spiritual realms. However, other secular rulers invoked this title to encourage papal intervention in worldly affairs. In letters ghostwritten by Peter of Blois, Eleanor of Aquitaine forcefully appealed to Celestine III as “vicar of the Crucified,” “successor of Peter,” and court of final appeal set over all peoples and kingdoms to intervene on behalf of her son, the crusader Richard I, who had been seized by a “tyrant” while under papal protection. Referencing Alexander III’s recent excommunication of emperor Frederick Barbarossa, she urged Celestine to wield the spiritual sword to avenge the injuries done to Christ and Peter and free her son. Her arguments anticipated potential objections: the Apostolic See (papacy) had passed sentence on imperial power before; papal power extended to bodies as well as souls; Celestine could use his own vicars (legates) and the threat of interdict and excommunication to free Richard; there was danger to papal authority if canon law protecting crusaders were restricted by “depraved laws” and “abominable customs.”Footnote ²⁹ The term “Vicar of Christ” would continue to play an important role in papal attempts to influence both temporal and ecclesiastical affairs in and beyond Latin Christendom throughout the twelfth and thirteenth centuries.

Innocent III: Reformer or Papal Monarch as Vicar of Christ?

Formerly depicted as a juristic and hierocratic pope intent on papal monarchy, Innocent III (r. 1198–1216) has been reconceived recently as a pastoral and reforming pope. However, interpretations of Innocent III’s claims for universal papal jurisdiction and the right to enforce peace, resolve cases, and appoint and depose kings are still hotly contested. Some, such as Brenda Bolton, have argued that Innocent based these claims on his duty, as Vicar of Christ, to judge sins rather than exercise universal temporal power. Others, as we will see below, claim that Innocent desired the political unity of Christendom under the pope (but only in order to promote reform), others that he envisaged two separate hierarchies of government (spiritual and temporal), both culminating in the papacy.Footnote ³⁰ No matter which portrait historians paint – Innocent III as responsive pastoral reformer or hegemonic “Lord of the World” – they agree that Innocent’s pontificate accelerated the tendency of the papacy to use temporal means to clarify and enact its spiritual role in a world defined by the growing influence of secular governments, eventually leading some temporal rulers to view popes as competitors.Footnote ³¹

By the time that Innocent III assumed office in 1198, the papal title “Vicar of Christ” was already linked to the growing political and ecclesiastical authority of the pope and a body of ecclesiological theory that portrayed the pope as the sole head of a unified Church. Although the suggestion that Innocent III was Huguccio of Pisa’s pupil has been successfully challenged by Kenneth Pennington, Huguccio summed up contemporary debates among canon lawyers: some applied the term “Vicar of Christ” to all priests, others claimed the pope alone was Vicar of Christ and of Peter, and as such exercised the power to correct and depose sinful rulers, a position Huguccio supported.Footnote ³² It appears that Innocent shared Huguccio’s convictions. His pontificate saw a marked increase in the usage of the papal title “Vicar of Christ” to justify papal intervention to create peace, reform Christendom, and promote the crusade. Innocent’s somewhat idiosyncratic usage of the term “Vicar of Christ” may have stemmed from his dual theological and legal training,Footnote ³³ but it caused problems and opportunities for contemporary and future canon lawyers, theologians, and political theorists. If, in the tradition of the priest–king Melchisedech, Christ’s reign was both spiritual and temporal, was that of his vicar as well? Although Innocent appears to have been a dualist in practice, his consistent use of “Vicar of Christ” seemed to imply a hierocratic system where both temporal and spiritual power culminated in and were wielded by the papacy. Most historians note that the full implications of Innocent’s claims would not be developed until the later struggles between Frederick II and Popes Gregory IX and Innocent IV. While thirteenth-century popes acknowledged the division of spiritual and temporal powers, they claimed the right to judge lay rulers and intervene in temporal matters. However, such elevated theoretical claims remained limited by popes’ ability to implement them through legates and local prelates.Footnote ³⁴

Traditionally, historians have turned to Innocent’s sermons and treatises to evaluate his conceptualization of the pope as “Vicar of Christ” within rich liturgical, exegetical, and ceremonial traditions. In a sermon for the feast of St. Sylvester, Innocent referenced the Donation of Constantine to affirm the joint priestly and kingly power exercised by the pope as Vicar of Christ.Footnote ³⁵ In another homily for his consecration as pope on the feast day of Saint Peter’s Chair (February 22, 1198), Innocent depicted himself as Peter’s successor and Christ’s vicar. Servant of the servants of God and pastor of God’s flock, he sits above kings and wields the power of the keys to uproot and plant (Jeremiah 1:10). Less than God but greater than man, the pope judges all and is judged by none but God (except in matters of faith), assertions commonly interpreted as reaffirmation of papal primacy and fullness of power. However, Innocent tempered these claims with an emphasis on awesome responsibility, duty to serve, and discretion. He nonetheless stressed that while other prelates shared pastoral responsibility, only Peter and his successor the pope received fullness of power as “vicar of Jesus Christ.”Footnote ³⁶

The ceremonial of Innocent’s consecration would have included a triumphal procession through Rome to Saint Peter’s, his celebration of the mass, delivery of the sermon, reception of the episcopal miter, and crowning with the papal tiara on the steps of Saint Peter’s (to represent secular authority), followed by a procession to the oratory of Pope Sylvester in the Lateran (where artwork depicted the Donation of Constantine and Investiture Conflict).Footnote ³⁷ Innocent’s sermon for the anniversary of his papal consecration similarly combined the language of duty and service with that of authority. The pope’s spiritual marriage to the Church entitled him to a dowry: “an abundance of spiritual gifts and an amplitude of temporal gifts …. For while others have been called to a portion of care [for the Church], Peter alone has been received into the plenitude of power.” The pope, as Christ’s vicar, is king of kings and lord of lords and so wears the tiara as a sign of imperial authority (and temporal power over the papal states) and the miter as a sign of his priestly authority, which is prior, worthier, and more extensive than imperial authority.Footnote ³⁸

Under Innocent III, papal aspirations to identification as the Vicar of Christ and of Peter were systematically explored through various forms of papal visual self-representation (artwork, liturgy, ceremonial, letters, seals). In a new apsidal mosaic added to Saint Peter’s, an enthroned Christ framed by Peter and Paul visually proclaimed the Petrine succession and primacy of Rome over other churches. In the lower register, situated between Bethlehem and Jerusalem, Innocent III, wearing a tiara as a symbol of the papal regnum, reverences Christ while spiritually marrying the Church. Innocent also paired himself in other artwork with Peter, Sylvester, and Constantine, while frescoes in the slightly later Sylvester chapel (c.1247) in the Quattro Coronati made similar visual arguments for the primacy of papal power derived from the Donation of Constantine (Figure 1.1).Footnote ³⁹

Figure 1.1 Saint Sylvester receives the tiara from Emperor Constantine, San Silvestro Chapel, Santi Quattro Coronati, Rome.

© Universal Images Group / Hulton Fine Art / Getty Images.

Between the eleventh and thirteenth centuries, papal ceremonial also depicted the pope, as Vicar of Christ, as the living image of Christ on earth.Footnote ⁴⁰ In a sermon delivered at the Fourth Lateran Council (1215), Innocent III presented himself as “another Christ” (alter Christus). Some historians have interpreted this council and its ceremonial as attempts to consolidate the shift from an episcopal-led to a papal-led Church, a movement which had begun with Gregory VII and would culminate with Boniface VIII.Footnote ⁴¹ However, many preachers and bishops traditionally cast themselves as an “alter Christus” when preaching and consecrating the Eucharist. In his treatise on the mass, in a chapter titled, “On the Primacy of the High Priest of Rome,” Innocent called the pope “Vicar of Christ,” but also acknowledged that all priests acted as vicars of the highest priest, Christ, in administering the sacrament of penance,Footnote ⁴² a sentiment reiterated in his sermons to priests.Footnote ⁴³ The power of the keys entrusted to Peter, to the pope as his vicar, and to all priests and bishops, enabled priests to absolve in confession and popes to issue indulgences as vicar of Peter and Christ. These metaphoric associations between Christ, popes, and priests had been directly challenged by dissidents who questioned the priestly ability to represent and summon Christ to physically indwell in the consecrated host and the priestly monopoly on preaching and the power of the keys, and the Fourth Lateran Council attempted to defend these associations.Footnote ⁴⁴ It is no accident that Innocent III’s sermon was delivered within a dialogic atmosphere where his stress on his duty to suppress heresy and implement reforms was contested by bishops, secular powers, and poets. As the pro-imperial Walter von der Vogelweide’s Disputation between Rome and the Pope bluntly proclaimed, exploiting the similarity between “vicar” (vicarius) and “stepfather” (vitricus): “You are no apostle but an apostate, nor pastor, / but rather a wolf, as your flock itself knows, nor father, but rather / stepfather of the Church.”Footnote ⁴⁵

Clearly, despite powerful visual and verbal symbolism, any claims to papal jurisdiction and power had to be carefully expressed and exercised. Many canonists and Innocent III himself acknowledged that rulers needed the consent of the governed and that bishops, too, were vicars of Christ within their dioceses.Footnote ⁴⁶ As “Vicar of Christ,” Innocent used his duty to reform the Church to redefine his relationship with bishops as first among unequals, to intervene in episcopal elections, and to remove and transfer bishops. In response, many bishops contested the increasing extension of papal provisions for prebends, dispensations, exemptions, and episcopal translations or depositions. Similarly, while some canonists granted extraordinary powers to the pope in theory, they carefully limited the implementation of these powers in practice. However, the growth of coherent collections of papal decretals and commentaries on them was accompanied by the strengthening of papal bureaucracy, the extension of papal jurisdiction through appeals to Rome, and the implementation of canon law by papal legates and judges delegate. These developments enabled some theoretical claims to universal papal monarchy to be implemented in practice by the mid- to late thirteenth century, a period when secular monarchs were using similar techniques to extend their powers at the expense of bishops and the local nobility. Arguments regarding papal supremacy over bishops within Church government soon extended to claims for fullness of power in both temporal and spiritual spheres.Footnote ⁴⁷

By vigorously adopting the title “Vicar of Christ” and aligning it with concepts of papal fullness of power and primacy, Innocent III created new theoretical justifications for the exercise of papal authority and attempted to apply those justifications in practice in novel ways. In Quanto personam (1198), Innocent stressed that the pope’s powers were bounded by custom, law, and tradition in the ordinary exercise of his office. Yet as Christ’s representative on earth, he exercised divine authority in certain special cases.Footnote ⁴⁸ It was Innocent’s responsibility to intervene in matters where sin had been committed by wielding the spiritual sword of excommunication and/or interdict. These matters included the recovery of territory considered part of the papal states, the creation of peace between Philip Augustus and John of England, and papal support of Otto IV, then Frederick II, as imperial candidates.Footnote ⁴⁹

In the case of John and Philip, Innocent’s intervention as arbitrator had been solicited by John, and the pope argued that, as Vicar of Christ, he was obliged to broker peace between his “sons.” Urged by papal threat of excommunication to make peace with his vassal John, Philip had previously summoned an assembly of lay and ecclesiastical magnates and with their support claimed that he was not obligated to submit to papal decisions on feudal matters. Canon lawyers and political theorists would make fruitful use of the famous decretal, Novit ille (1204), which Innocent in turn sent to French bishops. Innocent stressed that while he did not wish to diminish or interfere with Philip’s power, it was the pope’s duty to correct all sinners when the application of common law touched sin. As Vicars of Christ, popes had the ability to decide when circumstances required direct papal interference in temporal affairs, an argument Innocent again employed when using the Great Interdict to bring John of England to heel and when declaring the Magna Carta null and void. In response to Innocent’s assertion that all secular kings should venerate the pope and papal praise of John for submitting himself spiritually and temporally to he who unites kingship and priesthood in the vicariate of Christ (John had become a papal vassal), Philip Augustus curtly retorted that the kingdom of England never was nor would be part of Saint Peter’s patrimony and so was not under papal jurisdiction.Footnote ⁵⁰ In return, Innocent argued that as Christ’s vicar, it was his duty to require secular powers to cease hostilities (through threat of excommunication) to prevent needless deaths and danger to the crusade, even if neither party had asked for his intervention.Footnote ⁵¹ Philip was likely irritated by sweeping claims similar to those Innocent made to John: as a priest–king of the order of Melchisedech, Christ has appointed one universal vicar, to whom, as to Christ himself, every knee in heaven and on earth should bow, such that all obey and venerate him as God’s representative. Earthly kings should not consider themselves to rule legitimately unless they strove to faithfully serve the pope.Footnote ⁵²

Yet the very princes who most bitterly complained of papal interference in temporal affairs sought out that interference when it worked to their advantage; Philip Augustus petitioned Innocent III to retroactively legitimate his children by Agnes of Meran.Footnote ⁵³ Some of Innocent’s most overarching statements of papal authority were addressed to bishops in the papal states or were issued in response to a lay or ecclesiastical petitioner appealing to the pope as supreme arbiter. For example, William of Montpellier urged Innocent to extend his “full power” to dispense from illegitimacy as a bar to the episcopate to declare William’s children legitimate so that they could hold secular office, as Innocent had recently done for Philip Augustus. Innocent’s reply, Per venerabilem (1202), was quite cautious. As Vicar of Christ, the pope was the ultimate judge. In difficult and ambiguous cases involving both ecclesiastical and civil law (criminous clergymen, heretics, legitimacy), judgment could be referred to Rome and the ensuing sentences upheld by excommunication. The pope had full powers in temporal matters in the papal states and in some instances in other countries, but only on a case-by-case basis; this was not meant to prejudice secular rulers’ jurisdictional rights or powers.Footnote ⁵⁴

While Innocent refused William’s case because there was a secular authority William should have approached first (Philip Augustus), Per venerabilem introduced into medieval canon law a cluster of extensive pronouncements on the juridical rights of the pope to intervene in secular disputes when Innocent approved of its insertion into the decretal collection (Compilatio tertia) he sent to the law schools at Bologna. Later hierocratic theologians and popes such as Innocent IV utilized Per venerabilem to justify extensive claims to worldly power as Vicar of Christ.Footnote ⁵⁵ However, many early decretalists viewed with suspicion Innocent’s claim that, as Vicar of Christ, he could in theory legitimize in both the temporal and spiritual spheres. Commenting on Per venerabilem while still Sinobaldo Fieschi, the future Innocent IV declared that popes should not intervene in cases related to secular inheritance; temporal and spiritual matters were distinct and had different judges. Citing a novel authority from Deuteronomy, Per venerabilem had claimed universal papal appellate jurisdiction over temporal and spiritual matters, exercised at papal discretion. Innocent III was therefore neither dualist nor hierocrat; the papal “supreme court” defined its own jurisdiction. While he claimed supreme temporal authority, he delegated this authority to secular rulers, reserving the power to intervene, if necessary, to preserve Christendom.Footnote ⁵⁶

There was a radical difference between the papal claim to exercise indirect power in temporal affairs and the claim to exercise direct power in certain exceptional circumstances which the pope himself defined. Innocent III grounded his claim to jurisdiction in secular cases on the basis that he was the Vicar of Christ, who was both priest and king.Footnote ⁵⁷ Such papal statements often emerged in dialogue with claims and petitions originating from within and outside Latin Christendom. The papal decretal letters selectively compiled, taught, and commented on by canon lawyers helped to develop a system of law which prevailed in Church courts throughout Christendom; by the later thirteenth century, popes envisaged themselves issuing generally applicable laws. However, while specific circumstances shaped papal decretal letters, their rulings were often reinterpreted by commentators far removed from the original author and context. After Alexander III and Innocent III, canon lawyers possessed ample decretal letters to help them define precisely when popes could intervene in the temporal sphere.Footnote ⁵⁸ Decretalists turned to the concepts embodied in the term “Vicar of Christ” (as redefined in the letters and sermons of Innocent III) to support positions ranging from dualist (restricted and invited intervention in temporal affairs) to severely hierocratic (unlimited intervention in temporal affairs).Footnote ⁵⁹

In fact, many constitutional and legal historians, including Brian Tierney and James Watt, have claimed that Innocent III’s decretals were the very material some canon lawyers utilized to justify a shift from the “dualism” of the twelfth century to the “hierocratism” of the mid-thirteenth, which supposedly reached its apex in pro-papal writers such as Giles of Rome. Giles cited Per venerabilem to claim that all power, spiritual and temporal, was vested in the pope, who sometimes wielded temporal authority directly but more usually through secular rulers.Footnote ⁶⁰ However, Innocent III himself only rarely invoked the title “Vicar of Christ” to extend papal authority to the temporal plane in practice. In correspondence with the Greek patriarch of Constantinople, the Catholicos of Armenia, and the Greek emperors of Constantinople, Innocent claimed that as Vicar of Christ and Peter, the pope was responsible for teaching and governing the entire world.Footnote ⁶¹ At the request of a delegation sent by Kalojan, ruler of Bulgaria, who proffered the submission of the ruler and his Church to Rome, Innocent granted Kalojan the crown and title of king. Anticipating Byzantine critiques, Innocent invoked his ability to employ his universal spiritual jurisdiction as Christ’s and Peter’s vicar to intervene in temporal matters where necessary. Made after the Fourth Crusade’s diversion to Constantinople, Innocent’s decision reflected troubled Greco-Latin relationships and the potential threat Kalojan posed to the nascent Latin kingdom of Constantinople. Kalojan played on both, claiming that the Greek patriarch had pledged to crown him and make the archbishop of Trnovo a patriarch. By requesting that Innocent intervene instead, he appealed to Innocent’s conceptions of papal primacy and universal jurisdiction in spiritual and temporal matters.Footnote ⁶²

While Innocent III insisted that the pope, as Vicar of Christ, had the right to intervene in secular affairs and that the papacy was the supreme court of appeal, he did not always exercise this authority, reserved the right to define which cases were under his jurisdiction (in difficult and ambiguous matters, when there was no superior judge or the judge was biased), and could be inconsistent in his claims.Footnote ⁶³ Innocent III never invoked the title Vicar of Christ to claim unlimited power in the temporal realm; this occurred only with later popes such as Gregory IX and Innocent IV.Footnote ⁶⁴

Gregory IX and Innocent IV

Traditionally, scholars have condemned Innocent IV for exercising claims of papal supremacy, as Vicar of Christ, to defend his position as temporal ruler in Italy and for using both swords to do so: excommunication and deposition, ecclesiastical taxation, appointments of bishops, inquisitions, and indulgences and privileges granted for crusades against the Hohenstaufen and their supporters.Footnote ⁶⁵ However, Innocent III’s successors also invoked their position as “Vicar of Christ” to legislate, reform, and send out missions. Papal letters delivered by John of Plano Carpini to the Mongol ruler Güyük described the pope as Christ’s vicar wielding authority over and responsible for the salvation of both Christians and non-Christians. Despite John’s careful explication of Western political theory – the pope and emperor were the two supreme rulers from whom all other rulers derived their power – Güyük demanded that both bow to Mongol dominion.Footnote ⁶⁶ The Greeks remained similarly unconvinced, despite the efforts of Thomas Aquinas and others, before and after reunion attempts at the Second Council of Lyons (1274), to prove that Christ’s vicar exercised fullness of power over a global Church.Footnote ⁶⁷

Under Gregory IX, and more systematically, Innocent IV, the hierocratic concepts previously hybridized with the title “Vicar of Christ” by canonists were wielded systematically in papal correspondence to justify the rhetorical extension of the temporal power of the pope over the entire world. According to Innocent IV’s commentary on Quod super, the pope, as Christ’s vicar, possessed full power over both Christians and infidels. The conflict between Gregory IX, Innocent IV, and Frederick II came to a head with Frederick II’s deposition, for the criminal sins of perjury, sacrilege, and heresy, by Innocent IV as “Vicar, although unworthy of Jesus Christ” at the First Council of Lyons (1245). The ensuing propaganda war enabled the concept of the vicariate of Christ as conferring universal lordship in spiritual and temporal matters to be systematically explicated and contested. The contest was publicly staged; each side was cognizant that their arguments for authority had to appeal to varied audiences.Footnote ⁶⁸ Canon lawyers remained split between dualists (two vicars and two jurisdictions, temporal and spiritual) and hierocrats (one Vicar of Christ as head of the Church, who delegated the temporal sword to the emperor). To Hostiensis, the concept of two heads or vicars was monstrous. Citing Per venerabilem, he avowed there was one universal Vicar of Christ, the pope, whom all ought to obey. Theologians systematically worked out the ramifications of this position for papal authority over bishops and the global Church, while supporting the ability of popes to exercise temporal jurisdiction as well.Footnote ⁶⁹

The rhetoric of the vicariate of Christ and the two swords could be invoked to support papal–imperial collaboration as well as competition. While papal legate in Lombardy, the future Gregory IX had collaborated with Frederick II to suppress heresy and promote the crusade, although Gregory later wielded the spiritual sword of excommunication against Frederick to force him to fulfill his much-delayed crusade vow. He threatened that if the emperor despised this sanction he would proceed against him as a heretic and absolve his subjects from their oaths of loyalty.Footnote ⁷⁰ Gregory reminded Frederick that Honorius III had entrusted the material sword to Frederick and the emperor was bound to wield it for the good of Christendom. Frederick held lands in Italy as a vassal of Saint Peter and yet had attacked the papal states and local ecclesiastics, thereby making himself subject to the excommunication and potential deposition inflicted on fosterers of heretics and infidels.Footnote ⁷¹ Announcing that Frederick had ignored the spiritual sword and abused the temporal sword entrusted to him to attack papal possessions, Gregory directly wielded the temporal sword in defense of the Church, declaring what became known as the “War of the Keys.” Yet after the pope and emperor were temporarily reconciled, they issued a public statement of cooperation between the two swords, material and spiritual, in defense of the faith, the papal patrimony, and the Church. When conflict soon reemerged, Gregory IX invoked the Donation of Constantine to assert that the popes, as Christ’s vicars, were masters of all the faithful. He denounced Frederick for interfering with ecclesiastical property and persons in the papal states, thereby usurping papal fullness of power.Footnote ⁷²

Perhaps against the advice of many cardinals, by 1239 Gregory had excommunicated Frederick, summoned a general council, and initiated a publicity campaign via letters and legates. He accused Frederick of attacking the head of the Church, the Vicar of Christ, and rebutted Frederick’s claims that the pope and the Church’s ministers were hostile to the empire. He called on all secular and religious authorities to support him against Frederick on pain of excommunication. In response, Frederick maintained that imperial and ecclesiastical authorities should exercise their powers separately. Gregory IX was no true Vicar of Christ or successor to Peter or Sylvester; he abused the power of the keys and had attacked a legitimate emperor. Imperial polemicists turned Gregory’s appeal to the Donation of Constantine against the pope; Constantine had granted the Church whatever liberties and honors it possessed only because Constantine and Sylvester had a cooperative relationship. German bishops pleaded with the pope to form peace to aid the Holy Land, while Frederick publicly offered to bring his case before the cardinals and a general council composed of Church and secular authorities.Footnote ⁷³

After Gregory IX’s demise, the newly elected Innocent IV embraced the title “Vicar of Christ” and declared that he too was willing to submit the papal–imperial dispute to a general council. However, negotiations soon disintegrated and Innocent issued a public letter urging secular and ecclesiastical rulers to attend or send envoys to a council at Lyons that would rule on a list of charges against Frederick. Frederick’s representative, Thaddeus of Suessa, appealed to the gathered cardinals, claiming that Frederick feared that Christ’s vicar would wield the spiritual sword in a temporal way and proceed unjustly. Casting doubt on the legitimacy of the council, he urged the cardinals to reserve judgment to a future pope and a gathering that included Frederick’s peers: secular rulers.Footnote ⁷⁴ A veritable propaganda war and consensus-building campaign followed, and the council’s ensuing deposition of Frederick has been viewed as a landmark in the history of the papal monarchy.Footnote ⁷⁵

Innocent IV carefully represented this decision as pronounced by Christ’s vicar, who was capable of excommunicating and deposing Frederick after consulting with the cardinals and those assembled. However, after Thaddeus of Suessa accused Innocent of overreaching in depriving princes of their kingdoms and warned other secular rulers that they might be next, a member of Innocent’s inner circle drafted Eger cui levia (c.1246).Footnote ⁷⁶ The text defended Frederick’s deposition by claiming that Frederick had attempted to reduce to nothing the primacy of apostolic dignity Peter and his successors received from God. Popes acted as general legates of the king of kings; as Christ’s vicars, they possessed fullness of power to bind and loose in spiritual and temporal matters and the authority vested in both swords. A priest–king of the order of Melchisedech, Christ entrusted papal and royal monarchy to Peter and his successors, who reigned over both the heavenly and earthly empires. Constantine had recognized Christ’s vicar as the source of all sovereignty in surrendering his illegitimate authority and then receiving it back from Pope Sylvester. The material sword had been and always would be granted by popes to emperors and could be revoked. While citing the same authorities as Innocent III had and Innocent IV would in his more cautious canon law commentaries, the text made theological, hierocratic, and universal claims in reaction to the dualist assertions of Frederick II’s propagandists that the papal court had no right to judge emperors.Footnote ⁷⁷ Influenced by the widespread propaganda campaign, some secular rulers and theorists began employing the title “Vicar of God” to think about the exercise of political power. Alfonso X referred to himself as “God’s vicar” in Las siete partidas, while Pier delle Vigne famously appropriated papal chancery techniques and the title “Vicar of God” for propaganda in favor of Frederick II. The transfer of the concept of “Vicar of Christ” from theology and canon law to politics would help prepare the ground for the controversies of the fourteenth century.Footnote ⁷⁸

The extent of papal power in the temporal sphere even became the topic of quodlibets, academic questions openly debated before public audiences.Footnote ⁷⁹ One quodlibet was titled: “Whether the pope may command kings and princes in … all temporal things and whether they are bound to obey him in this.”Footnote ⁸⁰ The debater begins by asserting that it would seem so, as the pope is Christ’s vicar and possesses the same unrestrained power as Christ did, of ordering in all things. A counterargument drawn from civil and canon law is presented: although the pope is Christ’s vicar, he possesses the same powers only to the extent that Christ conceded them, that is, the spiritual power of the keys, not temporal kingdoms and jurisdictions. For Christ did not want to be a king among the apostles or a judge in matters of temporal inheritance but urged the apostles to render temporal things to temporal lords. The quodlibetist then cited Novit ille as an example of the pope’s right to intervene in matters of sin only, not in feudal matters. Similar to others, he sought to curb the authority Christ’s vicar exercised in the temporal sphere, in opposition to certain canonists, who attributed universal power to the pope. Although for some, the concept of the pope as Vicar of Christ seemed to imply that the Church possessed one head to which every power, earthly and spiritual, should answer, the ultimate consequences of this hierocratic theory of the two powers’ relation to each other had not yet been delineated. Both theories, the limiting and the universal, would play key roles during the conflict between Boniface VIII and Philip IV.Footnote ⁸¹

Boniface VIII (1294–1303) and Philip IV (1285–1314)

If the thirteenth century witnessed the zenith, in theory, of papal monarchy, fourteenth-century crises brought new challenges to the concept of papal supremacy. A veritable polemical storm was generated by the conflict between Boniface VIII and Philip IV, a struggle which stemmed from the growth of bureaucratic government and legal jurisdiction of each, leading to perhaps inevitable clashes over which possessed the power to authorize the taxation of clergy in France. Theologians, lawyers, and philosophers penned treatises in support of both sides, redefining the boundaries of the powers associated with the title “Vicar of Christ” during a public battle some historians have claimed led to the eventual decline of papal prestige and authority.Footnote ⁸²

On the pro-papal side, Tolomeo da Lucca, Giles of Rome, and James of Viterbo asserted that imperial power derived from the pope, who, as Christ’s vicar, possessed full power, both temporal and spiritual, over all humankind, in contrast to canonists and theologians who argued that, as a vicar, the pope was inferior to Christ and did not possess fullness of power. Arguments hinged on whether full powers resided in the office-holder only (Christ) or his vicar or representative (the pope). James interpreted “vicar” (vicarius) as meaning “in the place of” (vice); the pope’s powers were equivalent to Christ’s, not diminished (as in the case of a parish priest’s vicar). Therefore, the pope was supreme judge of the world in spiritual and temporal matters. At Boniface VIII’s behest, pro-papal apologists argued that spiritual power was greater than temporal; if papal power were supreme within the Church hierarchy, it must also be superior to temporal power in all matters. The pope was literally ruler of the entire world.Footnote ⁸³

Boniface VIII also appealed to hierocratic theory through visual imagery – he enlarged the papal tiara and commissioned statues of himself wearing it together with the papal miter (Figure 1.2).

Figure 1.2 Arnolfo di Cambio, bust of Pope Boniface VIII for his funerary monument on the altar of Saint Boniface in the Ancient Basilica of Saint Peter in Rome (1300).

© agefotostock/Alamy Stock Photo, n.d.

However, perhaps the most overlooked element of the polemical showdown between Boniface and Philip IV is the French bishops’ protests against the papal claims pronounced in Clericis laicos (1296) and Unam sanctam (1302).Footnote ⁸⁴ In Clericis laicos, Boniface denied that secular rulers possessed the right to tax Church property without papal permission, on pain of excommunication of both taxer and the taxed. After this particular struggle, like the investiture conflict before it, split the episcopate of France into pro-papal and pro-king camps, it was solved by compromise. Then, Philip IV’s arrest of the Bishop of Pamiers (then papal legate) triggered another struggle over control of the Church in France, culminating in Unam sanctam, perhaps the most forcefully systematic statement of papal primacy. The letter’s arguments were not new: there was only one head of the Church, Christ’s and Peter’s vicar, the pope, who held the power of both swords, granting the temporal to secular rulers, reserving the right to judge secular powers while being judged by none. Both sides in the conflict appealed to assemblies to back their authority and build consensus. Philip responded with action; forbidding French bishops to attend the council Boniface summoned for Rome, he assembled the estates, which rejected Boniface’s claims and charged the pope with heresy, magic, and sexual misdemeanors. Boniface VIII would die from injuries sustained during his arrest (by forces sent by Philip and two deposed Colonna cardinals), inflicted in a direct challenge to the concept of the sacrality of the pope’s body as Christ’s representative. The conflict graphically demonstrated the gulf between papal rhetoric and political reality.Footnote ⁸⁵

The struggle also spawned numerous treatises which outlined theories of government in support of both sides. While Giles of Rome and James of Viterbo made forceful cases for papal primacy and jurisdiction over earthly affairs and rulers, John of Paris claimed that temporal and spiritual power stemmed directly from God (not the pope) and should be exercised separately. Secular rulers governed communities for the common good while popes, as the head of the Church, spiritually ruled Christendom, but possessed no power to remove or appoint secular rulers, save in the papal states. In a harbinger of future events, he argued that popes who abused their spiritual power could be removed by the College of Cardinals or a council. His conclusions were shared by other influential writers, including Marsilius of Padua, Peter Olivi, and William of Ockham.Footnote ⁸⁶ In Questio in utramque partem (1302), an advocate for Philip IV argued that Christ granted only spiritual power to Peter as his vicar and that the vicariate did not extend to the temporal order or princes, particularly in France. The author directly combatted the hierocratic argument that the pope governed both spiritual and temporal matters as head of the Church. He followed some theologians in redefining the function and powers of vicars to restrict the papal vicariate to spiritual leadership alone, and he attacked the concept that the pope, as vicar, was equal in power to Christ, as did John of Paris and Dante.Footnote ⁸⁷ Other pro-royal polemicists reverted to the dualist concept of two vicars, while pro-papal theologians such as Raymond Lull, Duns Scotus, and Pierre Roger (the future Clement VI) reiterated that the pope was Christ’s universal vicar in spiritual and temporal matters alike.Footnote ⁸⁸ As following chapters will illustrate, the popes, as “Vicars of Christ,” would successfully navigate further challenges posed by their relocation to Avignon (1309–76), the Great Schism (1378–1417), strong monarchs, conciliarism, the Protestant Reformation, the Enlightenment, and the Age of Revolution.

Conclusion

The evolution of the papacy as an institution can be traced partly through assessing how shifts in the interpretation and usage of the title “Vicar of Christ” intersected with developing concepts of papal primacy and fullness of power and the theoretical and working relationships of individual popes to councils, the College of Cardinals, the episcopacy, secular rulers, and the global Church. However, within the history of the papacy, there is a tendency, still, to focus on defining “crisis points,” with the result that historians neglect long periods where the concept of the pope as “Vicar of Christ” enabled productive relationships between popes and secular rulers, Rome and local churches. New scholarship is beginning to investigate these relationships and the importance of intermediary figures such as legates, ambassadors, regional church leaders, and cardinals.Footnote ⁸⁹ For example, despite a pontificate wracked by papal–imperial tensions, schism, and that most famous of Church–state controversies (the murder of Thomas à Becket), Alexander III’s responsive papacy used decretal letters, legates, and councils to forge consensus, partly because, as an exiled pope, he relied on the good will of local rulers and prelates.Footnote ⁹⁰ And for all the tension between Gregory IX and Frederick II, there were also periods of harmonious collaboration facilitated by the mediation of the College of Cardinals, legates, and ambassadors. While the papal claim to exercise the vicariate of Christ was often challenged by secular powers, this typically did not, in the central Middle Ages, occur in the spiritual realm but in “grey areas” where earthly powers sensed that the vicariate of Christ was being wielded to intervene, in an unsolicited way, in matters critical to the definition of overlapping and occasionally competing spheres of government (episcopal, royal, noble, papal). The expansion of institutional structures and claim to titles expressing desire for greater jurisdiction and authority were shared by competing religious and secular powers around the globe, and the title “Vicar of Christ” was crucial to discussions of the theoretical extent of papal power and its implementation in practice for centuries. This centrality explains the storm of popular and learned controversy generated by the Annuario pontificio’s demotion of the title “Vicar of Christ” from the second official papal title to the backlist of historical titles in 2020.