Near the beginning of 897, Rome witnessed one of the most extraordinary proceedings in the history of Christianity. Pope Formosus had been dead for months. His body rested among the tombs of other popes at St. Peter’s, and two other men had already occupied the papal throne after his death. Yet under Pope Stephen VI, Formosus was summoned before a church council as though he could still answer charges brought against him.
His corpse was removed from its grave, dressed again in pontifical garments, and placed upon a seat before the assembled clergy. A deacon was appointed to speak on behalf of the dead pope. Formosus was then judged, condemned, ceremonially stripped of his papal dignity, mutilated, and removed from the place where popes were normally buried. His body would eventually be thrown into the Tiber.
The proceeding is usually known today as the Cadaver Synod, or Synodus Horrenda, the Horrible Synod. It is conventionally dated to January 897, although the surviving evidence does not allow such precision. Modern editions of the conciliar evidence cautiously place it in late 896 or early 897, while some modern scholars continue to use the traditional January 897 date. Even the location is less certain than popular retellings suggest. No surviving source definitively identifies the building where the trial occurred, despite the frequent claim that it took place in the Lateran Basilica.
There is another difficulty. The original acts of the Cadaver Synod no longer survive. They were condemned and ordered burned at the Synod of Ravenna in 898. The event therefore has to be reconstructed from the Ravenna proceedings, contemporary annals, and writings produced during the bitter controversy that followed.
That surviving evidence reveals something stranger than a grotesque spectacle. The trial of Formosus grew out of decades of disputes over papal authority, episcopal law, Roman factionalism, imperial politics, and the validity of ordination itself.
Formosus Before the Papacy
Formosus was already an important churchman long before he became pope. Born around 816, probably in Rome, he became bishop of Porto in 864 during the pontificate of Nicholas I. He gained particular distinction through missionary work. In 866 Nicholas sent Formosus and Bishop Paul of Populonia to Bulgaria after the recently Christianized ruler Boris sought closer relations with Rome.
The Bulgarian mission appears to have made a powerful impression. Boris reportedly wanted Formosus to become the head of the Bulgarian church, but such an appointment presented a canonical problem. Formosus was already bishop of Porto, and church law strongly discouraged a bishop from abandoning one episcopal see for another. The problem of transferring from one bishopric to another would follow Formosus for the rest of his life and eventually become one of the central accusations used against his papacy.
His career also brought him into the dangerous world of Roman politics. During the pontificate of John VIII, Formosus became associated with a faction that fell from favor. In April 876 he fled Rome with several other prominent men. Two Roman councils soon acted against the fugitives. Formosus was accused of abandoning his diocese, conspiring against papal and imperial authority, seeking advancement to another episcopal see, and maneuvering for the papacy itself. He was deposed, reduced to lay status, and excommunicated.
Formosus later appeared before John VIII at Troyes in 878. He received lay communion after agreeing in writing that he would not return to Rome and would not attempt to regain his former bishopric. After John VIII’s death in 882, however, the situation changed dramatically. Pope Marinus I permitted Formosus to return and released him from the earlier restrictions. By the middle of the 880s, Formosus had been restored as bishop of Porto.
When Pope Stephen V died in 891, Formosus was elected pope.
His elevation immediately revived the old canonical question. He had been bishop of Porto. Now he occupied the Roman see. The prohibition against episcopal translation was not an obscure technicality, even though exceptions had already occurred. For Formosus’s enemies, it offered a legal argument that could later be used to challenge not merely his behavior, but the legitimacy of his entire pontificate.
A Pope Between Rival Emperors
Formosus became pope during a period in which control of Rome and the imperial crown remained closely connected. The papacy could crown emperors, but powerful rulers could also place enormous pressure upon the pope who performed the coronation.
The dominant Italian dynasty was the house of Spoleto. Guy of Spoleto had already been crowned emperor, and in April 892 Formosus crowned Guy’s son Lambert as co-emperor at Ravenna. Relations between the papacy and the Spoletans deteriorated, however, and Formosus eventually looked beyond Italy for assistance.
In 893 papal representatives appealed to Arnulf of Carinthia, king of East Francia, asking him to intervene in Italy. Arnulf’s first expedition accomplished little. A second campaign beginning in 895 proved more formidable. Rome itself became caught between competing factions, with Lambert’s mother Ageltrude involved in the defense of the city against Arnulf’s forces.
Arnulf entered Rome in February 896. Formosus crowned him emperor. Arnulf then marched toward Spoleto, but illness, apparently a paralytic attack, brought the campaign to an abrupt end. He withdrew northward, leaving the political balance in Italy unsettled.
For generations, this episode supplied an apparently simple explanation for what came next. Formosus had abandoned Lambert for Arnulf. Lambert and Ageltrude therefore sought revenge once Arnulf withdrew, and Stephen VI later staged the corpse trial on their behalf.
The surviving evidence does not support that explanation as securely as it was once presented.
William Monroe’s detailed reexamination of the chronology points out that sources connecting Lambert and Ageltrude with the events do not actually say that they ordered the trial, or even demonstrate that they were in Rome when it occurred. More importantly, invalidating Formosus’s entire pontificate endangered Lambert’s imperial coronation as well as Arnulf’s. Modern scholarship therefore treats Roman ecclesiastical factionalism and Stephen VI’s own interests much more seriously than older accounts sometimes did.
The Death of Formosus
Formosus did not live long after Arnulf’s retreat. He died in Rome on April 4, 896, which was Easter Sunday, and was buried at St. Peter’s among his predecessors.
Boniface VI succeeded him but survived only about two weeks as pope. Stephen VI followed.
Stephen’s own position contained an uncomfortable connection to Formosus. Before becoming pope, Stephen had served as bishop of Anagni. Formosus had been involved in his elevation to that episcopal office. If the principle that a bishop could not transfer from one see to another made Formosus’s election as pope unlawful, the same reasoning raised awkward questions about Stephen’s own movement from Anagni to Rome.
Yet Stephen became the pope who pursued Formosus most aggressively.
The political situation had also changed. Arnulf’s influence over Rome weakened after his withdrawal, and Spoletan power recovered. By late 896 or early 897, the conditions existed for Formosus’s enemies to act against a man who could no longer defend himself.
Their response was not simply to condemn his memory.
They dug him up.
The Corpse Before the Council
The contemporary and near-contemporary accounts agree on the essential horror of what followed.
Formosus’s body was removed from its tomb. It was dressed in papal vestments and placed upon the apostolic seat. A deacon was stationed beside the corpse to answer the proceedings on behalf of the dead pontiff. The Annales Alamannici preserves this scene particularly clearly, describing Formosus as taken from his grave, placed on the apostolic throne, and given a deacon to respond for him.
The spectacle should not distract from the fact that the proceeding was structured as a church council. Stephen was attempting to produce a judgment with consequences for the institutional church. Formosus was not merely being insulted. His legal status as pope, his previous episcopal history, and the validity of actions performed during his pontificate were being attacked.
The precise accusations have to be reconstructed carefully because the original acts are gone. Later accounts give the proceedings dramatic dialogue, but those texts were written after the event. Liudprand of Cremona, writing decades later, famously presents the corpse as being challenged over why, while already bishop of Porto, Formosus had ambitiously seized the Roman see. Liudprand is important, but he cannot be treated as a verbatim transcript. He even attributes the proceeding incorrectly in his narrative.
The 898 Ravenna evidence and the earlier history of Formosus point toward two major issues. One concerned the promises connected with his reconciliation at Troyes in 878. Another concerned his transfer from Porto to Rome. Formosus’s enemies could argue that he had violated a sworn undertaking and had unlawfully left one episcopal see to occupy another.
Both were genuine canonical questions. Neither, however, required the physical presence of a decomposing corpse.
That was what made the proceeding extraordinary even to contemporaries.
The Condemnation of Formosus
The council found Formosus guilty.
His pontificate was treated as invalid, and his ecclesiastical acts were attacked with it. Of particular importance were the ordinations he had performed. Declaring those ordinations invalid threatened bishops, priests, and other clergy whose own authority depended upon having been ordained by Formosus.
This created consequences far beyond the punishment of one dead pope.
One of the most valuable witnesses to the controversy is Auxilius of Naples, a priest who had himself been ordained by Formosus. When Formosus’s ordinations were attacked, Auxilius had a personal reason to defend their validity. His writings are openly partisan, but precisely because the issue affected his own status, they preserve important evidence about the ecclesiastical crisis caused by the condemnation.
The sentence was also enacted physically upon Formosus’s body.
The papal vestments were removed. The corpse was dressed as a layman. Fingers were cut from his right hand. Popular accounts frequently state with certainty that three fingers were severed because those fingers had been used to bless and consecrate, but the surviving sources do not agree. Auxilius reports two fingers, while other traditions report three. The safest historical description is therefore that two or three fingers of Formosus’s right hand were cut away as part of the ritual degradation.
The physical mutilation gave visible form to the council’s judgment. The hand with which Formosus had blessed, ordained, and exercised papal authority was damaged. The vestments through which his office had been displayed were stripped away. The pope was symbolically transformed back into an ordinary man.
Even death had not protected his office, his body, or his memory.
From the Papal Tomb to the Tiber
The fate of the corpse did not end with the council.
The Annals of Fulda reports that Stephen ordered Formosus buried outside the customary resting place of the popes. Auxilius gives a more detailed sequence, describing the corpse as clothed in lay garments, mutilated, and placed in a burial place associated with outsiders or pilgrims.
Then the body disappeared from that grave as well.
It was taken out and thrown into the Tiber.
The precise circumstances vary between sources, which makes it dangerous to combine every surviving story into a single seamless narrative. Some accounts compress the movement of the body from the council to the river, while others indicate that Formosus was first reburied and only later disinterred again. The Ravenna evidence itself refers to removal from a tomb and disposal in the Tiber without making every stage of the chronology clear.
Later tradition held that fishermen recovered the body. The remains were eventually restored to St. Peter’s.
Liudprand would embellish that return with a miraculous story. According to his later account, images of saints or former popes bowed when Formosus’s body was brought back into the basilica. Whatever the value of that story as literal evidence, it demonstrates how the struggle over Formosus soon became a struggle over memory. To his enemies he had been a false pope whose body deserved degradation. To his defenders he could appear as a persecuted churchman whose remains were worthy of reverence.
Why Attack the Body?
The corpse is the central mystery of the Cadaver Synod.
If Stephen VI merely wanted a legal judgment against Formosus, the council could have condemned his actions without exhuming him. If the goal was only to invalidate questionable ordinations, a ruling could have been issued without dressing a dead man in papal vestments and placing him on a throne.
The physical presence of Formosus was therefore part of the meaning of the proceeding.
Michael Edward Moore has emphasized the importance of the body itself in understanding the trial. The punishment attacked the physical representation of papal authority. The corpse that had worn pontifical robes, occupied the papal seat, performed ordinations, and bestowed blessings was subjected to a reversal of those honors. The treatment of the body transformed theological and political condemnation into ritual humiliation.
Monroe has proposed an additional possibility. Formosus had long enjoyed a reputation for austerity and holiness, particularly because of his missionary career. In an age when formal papal canonization procedures had not yet developed into their later form, the tomb and physical remains of a revered religious figure could become a focus of popular devotion. Destroying or disposing of the corpse could therefore prevent a cult from developing around it. Monroe argues that the trial may have involved Roman enemies of Formosus attempting not simply to overturn his policies but to destroy the sacred memory gathering around him.
That interpretation remains an argument rather than a fact established explicitly by the sources. Still, it helps explain why a legal dispute over episcopal transfer and oaths escalated into an attack upon the dead pope’s physical remains.
The Cadaver Synod was not simply a court case held too late.
It was a ritual destruction of authority.
The Fall of Stephen VI
Whatever Stephen intended to accomplish, the proceeding did not settle Rome.
Contemporary sources show no admiration for what happened. Instead, the treatment of Formosus appears to have created scandal. Stephen’s position deteriorated rapidly.
By the summer of 897 he had been seized and imprisoned. In August he was strangled in confinement. A later epitaph associated with Pope Sergius III remembered Stephen’s imprisonment and violent death while defending his actions against Formosus.
The speed of Stephen’s fall demonstrates how unstable the Roman church had become. The Cadaver Synod had attempted to settle the legitimacy of one pontificate by erasing it, yet that judgment created new problems. If Formosus had never been a legitimate pope, what happened to the clergy he had ordained? What happened to bishops whom those clergy later ordained? What of papal acts issued during his reign? What of the men whose own offices depended upon decisions made by Formosus?
Trying to erase one pontificate risked throwing part of the church’s sacramental and administrative structure into confusion.
The controversy therefore continued after both Formosus and Stephen were dead.
The Rehabilitation of Formosus
Several short pontificates followed Stephen’s death. Pope Theodore II, who ruled for less than a month near the end of 897, began the rehabilitation of Formosus. Tradition associates Theodore with the recovery and honorable restoration of Formosus’s remains, although some details concerning a council under Theodore remain difficult to establish because of the complicated surviving manuscript evidence.
The more substantial reversal came under Pope John IX.
At Ravenna in 898, a council returned to the events of Stephen’s pontificate. Its surviving acts are the single most important official source for reconstructing the Cadaver Synod because they preserve evidence from men who had actually participated in Stephen’s assembly. Some admitted attendance but claimed that they had acted under compulsion. Others stated that they had signed the proceedings unwillingly. Bishops prostrated themselves and requested mercy, asking that churchmen never again be forced into actions contrary to canonical authority.
The Ravenna council reversed the attack against Formosus. His ordinations were defended, and the proceedings against him were condemned.
Then the council attacked the documentary memory of Stephen’s synod.
The acts of the Cadaver Synod were ordered to be publicly burned. The Ravenna council compared their destruction with the burning of records produced by earlier councils regarded as illegitimate or heretical.
The decision explains one of the great frustrations facing historians today. The church that reversed the corpse trial also destroyed the most direct record of it.
What survives is the testimony of those who opposed it, those who remembered it, and those who attempted to repair the damage it had caused.
The Formosan Controversy Continues
Ravenna did not permanently end the dispute.
Supporters and enemies of Formosus continued to struggle over his legacy. Under Sergius III in the early tenth century, anti-Formosan positions revived. The status of Formosus’s ordinations again became controversial, helping inspire the defenses written by Auxilius and Eugenius Vulgarius.
These writings are important because they show that the Cadaver Synod was not remembered merely because it was gruesome. The deepest problem involved continuity within the church.
Ordination was not an administrative appointment that could simply be erased from a ledger. If Formosus’s ordinations were invalid, clergy who derived their offices through him could face demands for reordination. That raised difficult theological questions about whether a sacramental act depended upon the later reputation or legal status of the bishop who performed it.
The corpse trial therefore touched a fundamental issue of ecclesiology. Could the church retroactively unravel sacramental history by declaring that the man who had performed those sacraments had never legitimately possessed his office?
Auxilius’s writings emerged from precisely this danger. His defense of Formosus was also a defense of priests like himself whose standing had been placed in question by Stephen’s judgment.
The dispute gradually faded, but it left behind a disturbing example of how political conflict and canon law could become entangled with sacramental legitimacy.
The Cadaver Synod in Historical Memory
The Cadaver Synod has often been presented as proof of the supposed barbarism of the late ninth-century papacy. Its imagery almost invites that interpretation. A decomposing pope sitting upon a throne while clergy judge him sounds less like institutional history than medieval horror.
Yet reducing the episode to madness or grotesque spectacle makes it harder to understand.
The men involved were disputing questions they regarded as profoundly serious. They were arguing about who could become bishop of Rome, whether a bishop could leave one see for another, whether sworn promises remained binding, whether papal acts could be reversed, whether ordinations performed by a condemned pontiff remained valid, and which political powers could legitimately claim imperial authority in Italy.
What made the Cadaver Synod extraordinary was the method through which those questions were confronted.
The participants did not allow Formosus simply to remain dead.
His corpse was transformed into evidence. His vestments became symbols that could be removed. His hand became an object that could be mutilated. His burial among the popes could be revoked. His body could be driven from one grave to another and finally cast into the river.
The resulting judgment proved impossible to contain. Stephen VI soon died violently. Formosus was rehabilitated. The council that reversed the proceeding ordered its records burned. Clergy spent years arguing over the ordinations that Stephen had attempted to erase.
Nearly all the most dramatic details must now be recovered from sources written by people who condemned the trial or lived with its consequences. The earliest evidence does not permit every familiar feature of the story to be stated with certainty. January 897 remains the conventional date rather than an unquestionable one. The Lateran remains a possible venue rather than a securely documented one. Even the famous severed fingers appear as two in some sources and three in others.
Those uncertainties make the episode more historically interesting, not less.
Behind the famous image of a dead pope sitting in judgment stands a church struggling over whether authority could survive scandal, whether ordination could survive condemnation, and whether the past itself could be reversed by decree. The Synod of Ravenna could burn Stephen’s records and restore Formosus’s name, but it could not erase what had happened.
More than eleven centuries later, the Cadaver Synod remains remembered precisely because Stephen VI attempted something far more ambitious than condemning a predecessor.
He tried to put the dead on trial.
Sources & Further Reading
Hartmann, Wilfried, Isolde Schröder, and Gerhard Schmitz, eds. Die Konzilien der karolingischen Teilreiche 875–911. Monumenta Germaniae Historica, Concilia 5. Wiesbaden: Harrassowitz Verlag, 2012. https://www.dmgh.de/mgh_conc_5/index.htm
Kurze, Friedrich, ed. Annales Fuldenses sive Annales regni Francorum Orientalis. Monumenta Germaniae Historica, Scriptores rerum Germanicarum 7. Hannover: Hahn, 1891. https://books.google.com/books?id=IrQElSW6-RUC
Reuter, Timothy, trans. The Annals of Fulda. Manchester Medieval Sources Series. Manchester: Manchester University Press, 1992. https://www.jstor.org/stable/jj.21995815
Pertz, Georg Heinrich, ed. Monumenta Germaniae Historica, Scriptores. Vol. 1. Hannover: Hahn, 1826. See especially the Annales Alamannici and Annales Laubacenses. https://www.dmgh.de/mgh_ss_1/index.htm
Auxilius of Naples. In defensionem sacrae ordinationis papae Formosi. In Ernst Dümmler, Auxilius und Vulgarius: Quellen und Forschungen zur Geschichte des Papstthums im Anfange des zehnten Jahrhunderts, 59–95. Leipzig: S. Hirzel, 1866. https://books.google.com/books?id=cSgPMMFMtVAC
Auxilius of Naples. Infensor et Defensor. In Patrologia Latina 129, cols. 1077–1102. https://la.wikisource.org/wiki/Infensor_et_defensor_%28Auxilius_Francus%29
Auxilius of Naples. De ordinationibus a Formoso papa factis. In Ernst Dümmler, Auxilius und Vulgarius: Quellen und Forschungen zur Geschichte des Papstthums im Anfange des zehnten Jahrhunderts, 107–116. Leipzig: S. Hirzel, 1866. https://books.google.com/books?id=cSgPMMFMtVAC
Auxilius of Naples. Libellus in defensionem Stephani episcopi et praefatae ordinationis. In Ernst Dümmler, Auxilius und Vulgarius: Quellen und Forschungen zur Geschichte des Papstthums im Anfange des zehnten Jahrhunderts, 96–106. Leipzig: S. Hirzel, 1866. https://books.google.com/books?id=cSgPMMFMtVAC
Eugenius Vulgarius. De causa Formosiana libellus. In Ernst Dümmler, Auxilius und Vulgarius: Quellen und Forschungen zur Geschichte des Papstthums im Anfange des zehnten Jahrhunderts, 117–139. Leipzig: S. Hirzel, 1866. https://books.google.com/books?id=cSgPMMFMtVAC
Dümmler, Ernst, ed. Gesta Berengarii Imperatoris: Beiträge zur Geschichte Italiens im Anfange des 10. Jahrhunderts. Halle, 1871. See especially Invectiva in Romam pro Formoso papa, 137–154. https://books.google.com/books?q=%22Gesta+Berengarii+Imperatoris%22+D%C3%BCmmler
Liudprand of Cremona. The Complete Works of Liudprand of Cremona. Translated by Paolo Squatriti. Washington, DC: Catholic University of America Press, 2007. https://www.cuapress.org/9780813215068/the-complete-works-of-luidprand-of-cremona/
Chiesa, Paolo, ed. Liudprandi Cremonensis Opera. Corpus Christianorum Continuatio Mediaevalis 156. Turnhout: Brepols, 1998. https://www.brepols.net/products/IS-9782503045610-1
Zucchetti, Giuseppe, ed. Il Chronicon di Benedetto monaco di S. Andrea del Soratte. Rome: Tipografia del Senato, 1920. https://archive.org/search?query=%22Chronicon+di+Benedetto%22+Zucchetti
Monroe, William S. The Trials of Pope Formosus. PhD diss., Columbia University, 2021. https://www.researchgate.net/publication/374697958_The_Trials_of_Pope_Formosus
Monroe, William S. “A New Look at the Cadaver Synod.” In Proceedings of the XV International Congress of Medieval Canon Law, Paris, July 2016, 321–355. Vatican City: Biblioteca Apostolica Vaticana, 2022. https://www.researchgate.net/publication/374697965_A_New_Look_at_the_Cadaver_Synod_Proceedings_of_the_XV_International_Congress_of_Medieval_Canon_Law_Paris_July_2016_Citta_del_Vaticano_Biblioteca_Apostolica_Vaticana_2022_pp_321-355
Moore, Michael Edward. “The Body of Pope Formosus.” Millennium 9, no. 1 (2012): 277–298. https://doi.org/10.1515/mjb.2012.9.1.277
Moore, Michael Edward. “The Attack on Pope Formosus: Papal History in an Age of Resentment (875–897).” In Ecclesia et Violentia: Violence Against the Church and Violence Within the Church in the Middle Ages, edited by Radosław Kotecki and Jacek Maciejewski, 184–208. Newcastle upon Tyne: Cambridge Scholars Publishing, 2014. https://www.cambridgescholars.com/product/978-1-4438-5882-3
Jégou, Laurent. “Compétition autour d’un cadavre. Le procès du pape Formose et ses enjeux (896–904).” Revue historique 675 (2015): 499–523. https://doi.org/10.3917/rhis.153.0499
Gnocchi, Claudia. “Ausilio e Vulgario. L’eco della ‘questione formosiana’ in area napoletana.” Mélanges de l’École française de Rome. Moyen Âge 107, no. 1 (1995): 65–75. https://www.persee.fr/doc/mefr_1123-9883_1995_num_107_1_3418
Duhr, Joseph. “Le Concile de Ravenne en 898: La Réhabilitation du pape Formose.” Recherches de Science Religieuse 22 (1932): 541–587. https://www.revue-rsr.com/article/le-concile-de-ravenne-en-898-la-rehabilitation-du-pape-formose/
Sansterre, Jean-Marie. “Formoso.” Dizionario Biografico degli Italiani 49. Rome: Istituto della Enciclopedia Italiana, 1997. https://www.treccani.it/enciclopedia/formoso_%28Enciclopedia-dei-Papi%29/
Loré, Vito. “Stefano VI.” Enciclopedia dei Papi. Rome: Istituto della Enciclopedia Italiana, 2000. https://www.treccani.it/enciclopedia/stefano-vi_%28Enciclopedia-dei-Papi%29/
Heckmann, Marie-Luise. “Der Fall Formosus: Ungerechtfertigte Anklage gegen einen Toten, Leichenfrevel oder inszenierte Entheiligung des Sakralen?” In Päpstliche Herrschaft im Mittelalter: Funktionsweisen, Strategien, Darstellungsformen, edited by Stefan Weinfurter. Ostfildern: Thorbecke, 2012. https://www.treccani.it/enciclopedia/papa-stefano-vi_%28Dizionario-Biografico%29/
Zimmermann, Harald. Papstabsetzungen des Mittelalters. Graz, Vienna, and Cologne: Böhlau, 1968. https://books.google.com/books?q=%22Papstabsetzungen+des+Mittelalters%22+Zimmermann
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Collins, Roger. Keepers of the Keys of Heaven: A History of the Papacy. New York: Basic Books, 2009. https://books.google.com/books?q=%22Keepers+of+the+Keys+of+Heaven%22+Roger+Collins