Pope Gregory IV (827-844)

A secondary pope, but a hinge pontificate

Gregory IV is not among the most famous popes. He lacks the political stature of Adrian I, the imperial prestige of Leo III, or the military role of Leo IV after the sack of Saint Peter's by the Saracens. His importance is more discreet: it shows what happens after the great Carolingian moment. The papacy had obtained a Frankish protector; it discovered that this protector could turn into a divided imperial family, capable of drawing the pope into its own quarrels.^[11][12]

This pontificate is thus a transitional chapter. It connects three worlds: aristocratic Rome, where the Roman laity weighed ever more heavily on elections; the Carolingian Empire, which claimed to control the regularity of pontifical elections; and missionary Christendom, looking toward Scandinavia via Hamburg, toward England via Canterbury, toward the Slavic and Danish world via the northern legations.^[13][14]

The first aftershock of the Constitutio Romana

In 824, Lothair I, son of Louis the Pious, had imposed the Constitutio Romana on Rome. The text confirmed the rights of Saint Peter, but it also framed pontifical elections: before any consecration, the pope-elect had to notify the emperor of his election, and the Romans swore an oath of fidelity to the Carolingian sovereign.^[15][16]

Gregory IV is the first pope whose election fully underwent this new machinery. According to the Annales regni Francorum and Treccani, he was elected after the death of the very short-lived Pope Valentine, but could be consecrated only after the arrival of an imperial envoy charged with examining the regularity of the election. The date of March 29, 828 retained by the Vatican reflects this delay.^[17][18]

The pope of a Rome still building

The Liber Pontificalis does not dwell first on the Frankish conflicts; it devotes much space to Gregory IV's Roman works. This choice is already an interpretation: for pontifical memory, Gregory remains a builder, restorer and liturgist pope. He rebuilt Saint Mark, his former presbyteral title, from the foundations; he restored Saint George in Velabro, the roofs of the diaconia of Saint Adrian and other places of worship; he fortified Ostia.^[19][20]

The apse mosaic of Saint Mark, still visible, gives the pontificate its finest image: the pope holds there the model of the basilica he offers, with a square halo indicating that he is depicted alive. The dedicatory inscription, whose published transcriptions diverge, is generally understood in this sense: Saint Mark is prayed to obtain for the pope long days and, after death, guidance to heaven.^[21][22]

Table of witnesses

The Liber Pontificalis: Rome telling its own story

The notice of Gregory IV in the Liber Pontificalis is precious because it gives the Roman memory of the pontificate. It reports that Gregory was the son of John, of Roman nobility, ordained by Paschal I, then attached to the title of Saint Mark. It also stresses his refusal of the office: he hid in the church of Saints Cosmas and Damian, before being found and led to the Lateran by the clergy and the people.^[23][24]

This detail must not be read as an isolated romantic scene. In pontifical notices, the candidate's hesitation often expresses a spiritual quality: the legitimate pope is not the one who throws himself upon the honor, but the one whom the Church must almost tear away from his humility. For Gregory IV, the motif meets another fact: the election was strongly carried by the Roman lay aristocracy, which perhaps explains the resistance of part of the clergy and the imperial delay.^[25]

The Frankish annals: the other side of the dossier

The Frankish sources are indispensable, for the major affair of the pontificate was played out north of the Alps. The Annales regni Francorum, Thegan, the Astronomer and the dossiers linked to Agobard of Lyon, Wala of Corbie and Paschasius Radbertus make it possible to follow the crisis of Louis the Pious. New Advent and the New Catholic Encyclopedia summarize this documentation: revolt of 830, restoration of Judith, new revolt of 833, displacement of the pope into Lothair's camp, meeting with Louis near Colmar, humiliating deposition of the emperor, then restoration of Louis in 834.^[26][27]

These texts do not say exactly the same thing as the Liber Pontificalis. The Roman source prefers building works, liturgy, the local Church. The Frankish sources show a pope drawn into a dynastic crisis. It is precisely the crossing of the two that gives the truth of the pontificate: Gregory IV is neither a pure builder of basilicas nor a Carolingian conspirator; he is a bishop of Rome attempting to exercise a peacemaking authority in an empire where family politics turn explosive.

The missionary and liturgical sources

The northern dossier rests principally on the Vita Anskarii of Rimbert, Ansgar's successor at Hamburg-Bremen. The text recounts how the organization of the Scandinavian mission was brought to Rome to receive pontifical confirmation; Gregory IV confirmed the office by decree, gave the pallium and established Ansgar as legate to the peoples of the North.^[28]

All Saints on November 1 rests on a more scattered liturgical tradition. Gregory III had already attached to Rome a solemn commemoration of all the saints around his oratory at Saint Peter's; under Gregory IV, Louis the Pious ordered the observance of this feast in the Frankish Empire, at the pope's instance and with the agreement of the bishops.^[29][30]

Family origin and formation

Gregory was born in Rome, on an unknown date, into a family of high rank. The sources give only his father's name, John. Treccani speaks of a Roman nobleman, and New Advent stresses his distinguished appearance and high birth.^[31][32] One must keep to these data: no documented childhood, no certain account of his formation, no developed genealogy.

His entry into the clergy took place under Paschal I (817-824), who ordained him priest according to New Advent and Treccani.^[33][34] The choice of Saint Mark was not insignificant: the title was ancient, in the heart of Rome, and Gregory would later leave there his most visible monumental work. His pontificate can thus be read as a return to his church of origin: as pope, he embellished the place where he had served as priest.

The election after the very brief pontificate of Valentine

His immediate predecessor, Valentine, died after an extremely short pontificate, in September 827 according to Treccani.^[35] Gregory's election took place with strong participation of the Roman lay aristocracy. It is a central trait of the 9th century: the nobility of Rome was no longer a mere spectator; it weighed upon the designation of the pontiff.

The Liber Pontificalis gives a favorable reading: they sought a man under whose doctrine and government the nobility of the senators might live uprightly.^[36] Treccani, more critical, also sees in it the sign of a balance of power. If the aristocracy supported Gregory, part of the clergy seems to have resisted, hence the recourse to imperial examination and the delay of consecration.^[37]

Six months of waiting before consecration

The decisive historical point is the delay. The Vatican file gives the beginning of the pontificate as "IX.827, 29.III.828": the election belongs to 827, the consecration to March 29, 828.^[38] New Advent indicates that imperial intervention caused such a delay that he probably began to govern only around March 828.^[39]

This waiting makes Gregory IV a test case of the Constitutio Romana. The pontifical election remained Roman; but the consecration could no longer ignore the Emperor. The papacy, having become the partner of the Carolingians, discovered here the institutional price of that alliance.

The division of 817 and the birth of the conflict

To understand 833, one must go back to the Ordinatio imperii of 817. Louis the Pious, son of Charlemagne, then organized the Empire around his eldest son Lothair, associated to the Empire, while giving subordinate kingdoms to his other sons, Pepin of Aquitaine and Louis the German.^[40][41] The system sought imperial unity, but it prepared jealousy.

After the death of his first wife, Louis married Judith of Bavaria. Their son Charles, the future Charles the Bald, in turn received a share of the inheritance. The elder sons saw in it a threat. A first revolt broke out in 830; Judith was separated from Louis and forcibly veiled. But an assembly at Nijmegen, then a diet at Aachen, restored the imperial couple. New Advent specifies that this restoration also came about by decision of the pope and other bishops.^[42][43]

Why did Gregory cross the Alps?

In 833, the sons rose again. Lothair, who governed Italy, drew Gregory IV across the Alps. The sources do not allow the pope to be reduced to a puppet, but they clearly show that he was used: his presence in the sons' camp gave the revolt an appearance of religious legitimacy.^[44][45]

The bishops faithful to Louis then refused to come to the pope, because they suspected his good faith. Gregory answered firmly: he claimed the right of the Apostolic See to intervene for the peace of Christendom. Treccani speaks of a harsh, polemical reply, almost a historical manifesto of the rights of the papacy against the Empire.^[46]

"the bishops who remained faithful to the emperor, suspicious of the pope's good faith, would not come to him when he summoned them to his presence" — Horace K. Mann, summary of the 833 dossier in the Catholic Encyclopedia^[47]

The "Field of Lies"

The meeting took place near Colmar, in the place that memory would call the Lügenfeld, the Field of Lies. Gregory eventually met Louis, but Louis did not trust him. During the negotiations, Lothair worked on his father's military loyalties; the imperial army disintegrated; Louis fell into the hands of his sons.^[48][49]

The sequence was tragic for all. Louis was humiliated, deposed, subjected to public penance. Lothair took power. Gregory, who had probably hoped to impose peace, returned to Rome compromised, deceived and politically weakened. New Advent harshly summarizes that he returned "a sadder and a wiser man".^[50]

A failed mediation, not an anti-imperial doctrine

It would be too simple to make Gregory IV an anti-imperial pope. He did not seek to destroy the Carolingian Empire; he sought to restore peace to it. But he underestimated Lothair's capacity to use the pontifical presence as a symbolic weapon. The problem was not the pope's doctrine, but the political reading of the situation.

The failure nevertheless has long reach. It reveals that the pope can now be summoned into the internal crises of the Empire; conversely, it reveals that the Empire can attempt to neutralize or instrumentalize the pope. The great alliance of 800 between Leo III and Charlemagne became, a generation later, a field of ambiguities.

Louis restored, Lothair isolated

Louis the Pious was restored in 834. Lothair withdrew to Italy. The pope did not break communion with the restored emperor, but trust was damaged. The New Catholic Encyclopedia mentions that in 837 Louis sent Abbot Adrebald to Rome to consult the ailing pope, while Lothair harassed ecclesiastical goods in Italy.^[51]

This late phase is less spectacular, but it shows a Gregory IV less master of events than he would have wished. He had to hold Rome, Italy and imperial relations, while watching the Carolingian order crack.

The death of Louis and the failure of peace between the sons

Louis died in 840. Lothair then sought to obtain the Empire in fact, not only in title. Gregory sent a legate, Archbishop George of Ravenna, to attempt to maintain peace between the sons.^[52][53] The attempt failed.

In 841, the battle of Fontenoy-en-Puisaye pitted Lothair and Pepin II of Aquitaine against Charles the Bald and Louis the German.^[54] New Advent sees in it the near-destruction of unified Frankish power and the practical end of the Carolingian Empire as a coherent political reality.^[55] Gregory was not responsible for this catastrophe; he was its powerless witness.

A pope in a fragmenting Christendom

Gregory IV's pontificate thus heralds a major fact of the 9th century: Western Christendom remained one, but its political unity fragmented. The pope had henceforth to speak to several Frankish kings, not to a single Charlemagne. This plurality would open margins of action to Rome, but also contradictory pressures.

In this perspective, Gregory IV is less a weak pope than a pope placed in a weak conjuncture. His errors exist; but the crisis went beyond his person. It came from the very structure of the Carolingian inheritance: the Empire wanted to be one, the sons wanted their kingdoms, the bishops took sides, and the pope sought a peace that arms made impossible.

Saint Ansgar and the mission of the North

The most positive dossier of the pontificate is probably the northern mission. Ansgar, monk of Corbie then missionary, became the great apostle of Scandinavia. After the foundation of the see of Hamburg as a missionary base, the Vita Anskarii of Rimbert reports that Gregory IV confirmed his role, gave him the pallium and named him pontifical legate to the peoples of the North.^[56][57]

Rimbert's text (ch. XIII) thus reports that the pope confirmed the organization of the mission by a decree of authority and by the gift of the pallium, and established Ansgar as his legate to the Swedes, the Danes, the Slavs and the other northern peoples.^[58] In the long history of evangelization, this gesture counts for more than the political failures of 833. It attached the first missionary structures of Scandinavia to Saint Peter. The authenticity of the pontifical privilege thus described nevertheless remains debated by scholars, the Hamburg-Bremen dossier mixing authentic pieces and forged ones.^[59]

Salzburg, Canterbury, Grado and Le Mans

According to Horace Mann's synthesis in the Catholic Encyclopedia, Gregory IV also conferred the pallium on the archbishops of Salzburg, Canterbury and Grado.^[60] These gestures show a papacy of communion: Rome did not direct every detail of the local Churches, but it marked the metropolis, confirmed a jurisdiction, arbitrated conflicts.

The case of Grado prolongs the old conflict with Aquileia. By supporting Grado against the encroachments of Aquileia, Gregory intervened in the ecclesiastical geography of the Adriatic, a sensitive zone between Frankish Italy, the Byzantine heritage, the Venetian world and rival patriarchates.^[61]

Aldric of Le Mans

According to the same synthesis, Gregory also supported Aldric, bishop of Le Mans, who had suffered for his fidelity to Louis the Pious against the rebels.^[62] This detail nuances the image of a Lothairian pope. Even after the catastrophe of 833, Gregory was not simply one party's man. He could support a bishop faithful to Louis when ecclesial justice required it.

Saint Mark: Gregory IV's personal monument

The basilica of Saint Mark at the Capitol is Gregory IV's principal monument. Treccani specifies that he rebuilt the edifice a fundamentis, after demolition of the previous state, and decorated it with an apse mosaic in which the blessing Christ is surrounded by saints and by the pope himself bearing the model of the church.^[63][64]

For the article, this is the most important visual. It must not be replaced by a generic image of a pope. The mosaic is contemporary with the pontificate, visible, localized and theologically eloquent: Gregory does not place himself at the center; he offers the church to Christ through the intercession of Saint Mark.

Saint George in Velabro and Saint Adrian

The same Roman dossier includes Saint George in Velabro, by the Forum Boarium, and the diaconia of Saint Adrian on the Sacred Way. Treccani recalls that scholars debate the exact extent of the interventions at Saint George, but that the most solid hypothesis attaches the main structure of the present edifice to Gregory IV's remodelling.^[65]

These works belong to a continuous line: since Adrian I, Leo III and Paschal I, the Carolingian popes did not content themselves with diplomacy. They built, restored, decorated, organized the diaconiae and sanctuaries. Christian Rome was governed by stone, mosaic, liturgy and almsgiving as much as by letters.

Gregoriopolis: Ostia facing the Saracen threat

At the beginning of the 9th century, the Saracens advanced in the western Mediterranean. They seized Sicily and began to intervene in the wars of the princes of southern Italy.^[66] Rome was not yet struck as it would be in 846, but the mouth of the Tiber became a vulnerable point.

Gregory IV responded by fortifying ancient Ostia, which he renamed Gregoriopolis. New Advent sees in it a measure taken for the security of Rome; studies on Ostia recall that the new town was built east of ancient Ostia, as a fortified post against Arab raids.^[67][68]

This undertaking heralds the more massive responses of Leo IV after 846: naval victory at Ostia, Leonine walls around Saint Peter's, military defense of the Vatican zone. Gregory IV was thus the pope of the first alarm; Leo IV would be the pope of the counterstroke after the trauma.

From Gregory III to Gregory IV

The history of All Saints on November 1 did not begin with Gregory IV. Under Gregory III, an oratory at Saint Peter's had already been dedicated to all the saints, and November 1 became in Roman tradition a major date of commemoration.^[69][70]

Gregory IV intervened a generation later, not to invent the feast, but to extend it in the Frankish world. According to liturgical syntheses and the New Catholic Encyclopedia, Louis the Pious ordered the observance of the feast in his territories at the instance of Pope Gregory IV and with the agreement of the bishops.^[71][72]

A Roman feast become Western

The gesture mattered: a feast attached to the Roman memory of martyrs and saints progressively became a feast of the whole Latin Church. The calendar was no secondary detail. It shaped the common memory: each year, on November 1, the Church looked not only to the saints known by name, but to the whole multitude of the saved.

In a Catholic encyclopedia, this point deserves emphasis. Gregory IV was not only the pope of the Field of Lies. He was also one of the popes through whom a Roman liturgical intuition became a common good of Western Christendom.

"he instructed him to proclaim the observance of the feast of All Saints throughout the empire" — Horace K. Mann, summary of the liturgical tradition in the Catholic Encyclopedia^[73]

Death on January 25, 844

Gregory IV died in Rome on January 25, 844.^[74][75] He was buried at Saint Peter's, in the Vatican basilica. His death opened the way to the election of Sergius II, in a Roman context still more marked by the aristocracy and soon struck by the Saracen raid of 846.^[76][77]

The pontificate lasted about sixteen years from the election, a little less if counted from the consecration. Its length contrasts with the impression of political failure left by 833. Gregory governed for a long time; but the most famous event of his reign was the one over which he had least control.

A fourfold legacy

How should he be judged?

The historical judgment must remain sober. Gregory IV was neither a great strategist nor a negligible pope. He failed in the Carolingian dossier, but he did not abandon his mission of peace. He endured imperial control, but he also affirmed the rights of pontifical authority. He did not prevent Frankish fragmentation, but he supported the northern mission, the liturgy of All Saints and the concrete defense of Rome.

His life recalls an important law of Church history: secondary pontificates are not parentheses. They often bear the consequences of previous great gestures. Leo III had crowned Charlemagne; Gregory IV had to live with the divided sons of that Empire.

Did Gregory IV create the feast of All Saints?

Not exactly. The collective commemoration of the saints predates him, and November 1 was already linked to Rome under Gregory III. Gregory IV is chiefly associated with the extension of this feast to the Frankish world, through Louis the Pious, which helped fix November 1 durably as the Western date of All Saints.^[78][79]

Did he support the rebellion against Louis the Pious?

His presence in Lothair's camp in 833 objectively served the rebels, but the sources suggest he intended to exercise a mediation of peace. Lothair used him. The result was disastrous: Louis was abandoned by his troops, deposed and humiliated, while Gregory returned to Rome weakened.^[80][81]

Why was his election delayed?

Because of the imperial control established in the context of the Constitutio Romana of 824. Louis the Pious's representatives demanded that the election be examined before consecration. Gregory, elected in 827, was consecrated only on March 29, 828.^[82][83]

Which image should be preferred for the article?

The mosaic of San Marco in Rome takes priority: it is directly linked to Gregory IV, shows him alive with a square halo, and depicts his major work of reconstruction. A map of Gregoriopolis and a Carolingian frieze may complement it, but not replace this monumental witness.

• Pope Saint Gregory III (731-741) — Roman origin of All Saints on November 1 and context before Gregory IV.
• Pope Adrian I (772-795) — Carolingian alliance, political birth of the medieval papacy.
• Pope Saint Leo III (795-816) — imperial coronation of Charlemagne.
• Pope Sergius II (844-847) — immediate successor, on the threshold of the Saracen raid of 846.
• The old basilica of Saint Peter in Rome — place of pontifical memory and burial.