The Grisly Story Of The Cadaver Synod, When A Pope’s Rotting Corpse Was Put On Trial

Published October 19, 2017
Updated July 1, 2025

In 897 C.E., the corpse of Pope Formosus was exhumed and put on trial by one of his successors, Pope Stephen VI — and Formosus was found guilty.

Cadaver Synod

Nantes Museum of ArtsDuring the Cadaver Synod, one pope dug up the corpse of another pope and put the body on trial.

The Catholic Church has put many people on trial, including Galileo, Joan of Arc, and Martin Luther. But the strangest trial in church history took place in the ninth century. Known as the Cadaver Synod, it was the trial of Pope Formosus — who had died eight months before.

Though Pope Formosus was dead, his prosecutors were undeterred. The pope’s body was exhumed, dressed in papal vestments, and perched on the stand. During the trial, which took place in January 897, Formosus was even found posthumously guilty of perjury and other crimes.

So how did the Cadaver Synod even take place? And what was the punishment for a pope who had already died?

This is the strange story of the Cadaver Synod, the ninth-century trial of a dead pope that horrified all of Rome.

Pope Formosus, The Pope At The Center Of The Cadaver Synod

Pope Formosus

Public DomainPope Formosus was the dead pope put on trial during the Cadaver Synod.

The dead pope on trial during the Cadaver Synod was Pope Formosus, who was pope from October 891 until his death in April 896.

Formosus came to power during a chaotic time in the history of the Catholic Church. The political landscape of Europe was changing rapidly, and clergy members were increasingly forming different factions.

It was in this atmosphere that Formosus, while still the Bishop of Porto, was accused by the current pope, Pope John VIII, of two serious crimes. John claimed that Formosus was ruling in more one place at once and that he was openly campaigning to become pope himself. He had Formosus excommunicated — but the excommunication didn’t last.

John was assassinated in 882. His successor, Marinus I, reinstated Formosus, but died about a year later. Marinus’ successor, Pope Adrian III, also died after only a year in power, and his successor, Pope Stephen V, reigned for six years before his death. Then, Formosus became pope in 891.

Though Formosus’ own reign was short-lived, he threw himself into the political disputes of the day. Formosus first supported Lambert of Spoleto to become the Holy Roman Emperor, for example, before switching his alliance to Arnulf of Carinthia while Lambert was still alive.

Pope Formosus Painting

Wikimedia CommonsBefore becoming pope, Formosus was known as a missionary who traveled through Bulgaria.

Then, Formosus died of natural causes in April 896 while in his eighties. He was succeeded by Pope Boniface VI, who ruled for just two weeks before his death, then by Pope Stephen VI.

It was Pope Stephen VI who decided to dig up Formosus’ corpse and put it on trial during the infamous Cadaver Synod.

The Gruesome Story Of The Cadaver Synod

In January 897, Stephen VI made an unusual decision. He called for Pope Formosus’ body to be exhumed, clad in papal vestments and put on trial. While historians originally believed that Stephen VI’s actions were politically motivated, and linked to Formosus’ back-and-forth between Lambert and Arnulf, his true motivations may have been much simpler.

Stephen VI wanted to stay in power.

Technically, Stephen VI had become pope (the Bishop of Rome) while still a bishop elsewhere. Formosus had appointed him as bishop originally, but it was against church law to hold two offices at once. So, Stephen VI possibly thought that if he could nullify Formosus’ time as pope, he could legitimize his own.

Pope Stephen Vi

The History Collection / Alamy Stock PhotoPope Stephen VI, the pope who ordered the Cadaver Synod.

Thus, the Cadaver Synod began. During the trial, Pope Formosus was propped up in a chair and made to answer for his “crimes,” much to the horror of many people in Rome.

As Formosus’s corpse rotted on the stand, Stephen VI laid out his case.

He claimed that the ex-pope had broken canon law by trying to hold multiple bishoprics at the same time. (The church had banned that practice to avoid bishops becoming too powerful.) Formosus also faced accusations of perjury after purportedly promising not to pursue church positions but then accepting the title of pope. Finally, Stephen declared that Formosus had broken an oath he had once allegedly taken to remain a layman.

During the Cadaver Synod, an earthquake rocked Rome, which many took as a sign of displeasure from God. But the trial continued.

Cadaver Synod Depiction

CBW / Alamy Stock PhotoAnother depiction of the Cadaver Synod.

And at the end, Pope Formosus was found guilty on all counts.

The Punishment Of Pope Formosus — And Pope Stephen VI

At the end of the Cadaver Synod, Pope Formosus was stripped of his papal vestments. Three fingers on the hand he used for blessings were cut off, and Formosus’ actions as pope were nullified. Then, his corpse was buried, dug up again, and thrown in the Tiber River.

The Tiber had long been used by the people of Rome to dispose of the most detested criminals, from citizens to disgraced emperors.

Tiber River In Rome

Statens Museum for Kunst The Cadaver Synod ended with the dead pope’s body thrown into the Tiber.

But Pope Formosus’ body would not stay there. It was quietly recovered, either by a monk or a fisherman. And Stephen VI soon faced a punishment of his own.

The Cadaver Synod had not been popular. Rather, it struck most as a gruesome, obscene spectacle, and many of Stephen VI’s former supporters turned against him. The people of the city rose up and threw Stephen VI into prison, where he was soon strangled to death in August of 897.

Even his death did not create stability in the church, however. Stephen VI’s successor Pope Romanus held the papacy for only a few months, and the next pope, Theodore II reigned for just for 20 days. During that time, Theodore II nevertheless managed to recover Formosus’ body, and Theodore II’s successor, John IX, ensured that Formosus was buried in St. Peter’s Basilica alongside many of the popes who had come before him.

With that, the gruesome story of the Cadaver Synod came to an end. Today it stands as a bizarre and grisly chapter in Catholic Church history, not only embodying the chaotic era of multiple, short-lived popes (there were 17 in the ninth century), but also the outlandish actions of one man. Stephen VI’s decision to put a dead pope on trial was a shocking one, as unpopular in his time as it is disturbing today. It’s no wonder that in Latin, the Cadaver Synod is called the Synodus Horrenda, or the Horrible Synod.


After learning about the bizarre story of the Cadaver Synod, discover the stories of some of the Catholic Church’s most colorful popes. Or, read about some of the most terrifying real-life exorcisms to ever take place.

author
Genevieve Carlton
author
Genevieve Carlton earned a Ph.D in history from Northwestern University with a focus on early modern Europe and the history of science and medicine before becoming a history professor at the University of Louisville. In addition to scholarly publications with top presses, she has written for Atlas Obscura and Ranker.
editor
John Kuroski
editor
John Kuroski is the editorial director of All That's Interesting. He graduated from New York University with a degree in history, earning a place in the Phi Alpha Theta honor society for history students. An editor at All That's Interesting since 2015, his areas of interest include modern history and true crime.
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Carlton, Genevieve. "The Grisly Story Of The Cadaver Synod, When A Pope’s Rotting Corpse Was Put On Trial." AllThatsInteresting.com, October 19, 2017, https://allthatsinteresting.com/cadaver-synod. Accessed July 10, 2025.