Cadaver Synod (897): Pope Formosus Put on Trial After Death

The Cadaver Synod was a church trial held in Rome in January 897 at which Pope Stephen VI had the decaying corpse of his predecessor, Pope Formosus, exhumed, dressed in papal robes and put on trial. The dead pope was found guilty, his acts were annulled and his body was mutilated and thrown into the River Tiber. The macabre event, also called the Synodus horrenda, became a symbol of the violent factional politics that engulfed the papacy at the end of the 9th century.

Background: a papacy caught between factions

By the late 9th century, the Carolingian empire created by Charlemagne’s coronation in 800 had broken apart. Popes ruled central Italy as territorial lords, a role rooted in the Donation of Pepin in 756, but they had no reliable protector. Roman aristocratic families and Italian princes competed to control papal elections and, with them, the right to crown an emperor.

Formosus, born around 816, was an experienced churchman. As bishop of Porto, near Rome, he led a mission to Bulgaria in 866 and served as papal legate on other diplomatic missions. In 876 Pope John VIII accused him of conspiracy and excommunicated him. He was later allowed back to lay communion on condition that he swore never to return to Rome or exercise his office as a priest. Pope Marinus I restored him to Porto in 883.

The pontificate of Formosus

Formosus was elected pope in October 891. At that time, Guy of Spoleto, a powerful duke from central Italy, had already been crowned emperor. In 892 Formosus crowned Guy’s son Lambert as co-emperor, apparently under pressure.

Seeking an alternative, Formosus appealed to Arnulf of Carinthia, the East Frankish king. Arnulf marched into Italy, took Rome in February 896 and was crowned emperor by Formosus. Soon afterwards Arnulf was struck by paralysis and returned north, leaving the Spoleto party, led by the young Lambert and his mother Ageltrude, in a strong position. Formosus died on 4 April 896.

His successor, Boniface VI, died after about two weeks. The next pope, Stephen VI, elected in May 896, was close to the Spoleto faction, though he had been made bishop of Anagni by Formosus himself.

What happened at the synod

In January 897, around nine months after Formosus’s death, Stephen VI convened a synod in the Lateran Basilica, the pope’s cathedral in Rome. Formosus’s body was taken from its tomb, clothed in full pontifical vestments and seated on a throne. A deacon was appointed to answer on his behalf.

Stephen himself conducted the questioning. According to the surviving accounts, the charges were that Formosus had moved from the see of Porto to that of Rome, which church law at the time generally forbade for bishops, that he had broken the oath he had sworn under John VIII, and that he had acted as a bishop while under that ban. The outcome was decided in advance.

The synod declared Formosus unworthy of the papacy and his election invalid. All his acts were annulled, and the clergy he had ordained were to be re-ordained or removed. His vestments were stripped, and the three fingers of his right hand used for papal blessings were cut off. The body was buried in a common grave and then thrown into the Tiber.

The details of the scene come mainly from sources written soon after, including defences of Formosus by the cleric Auxilius and the grammarian Eugenius Vulgarius, and from the historian Liutprand of Cremona, writing in the mid-10th century. The decision to annul Formosus’s ordinations was what most concerned contemporaries, because it threw into doubt the status of many priests and bishops.

Key people

Formosus (c. 816–896) was pope from 891 to 896. His career as a missionary and diplomat made him prominent, but also exposed him to enemies within the Roman church.

Stephen VI (died 897) was pope from 896 to 897. He is sometimes numbered Stephen VII because of confusion over an earlier pope-elect named Stephen who died before consecration in 752.

Lambert of Spoleto (died 898) and his mother Ageltrude led the Spoleto faction, which opposed Arnulf’s claim. Historians often see their influence behind the synod, though their exact role is not documented.

Arnulf of Carinthia (died 899) was crowned emperor by Formosus in 896, an act that made Formosus a target for the Spoleto party.

Consequences

The trial provoked outrage among many Romans. According to later reports, the Lateran Basilica partly collapsed around this time, which some took as divine judgement, and the body of Formosus was said to have been recovered from the Tiber and to have worked miracles.

In the summer of 897 Stephen VI was overthrown by a popular uprising, imprisoned and strangled. His successor, Romanus, reigned only a few months. Pope Theodore II, who reigned for about twenty days in late 897, annulled the Cadaver Synod, restored the clergy ordained by Formosus and had the recovered body reburied with honour in St Peter’s Basilica.

In 898 Pope John IX held synods in Rome and Ravenna that confirmed Formosus’s rehabilitation, ordered the records of the Cadaver Synod destroyed and forbade trials of the dead. The dispute did not end there. Pope Sergius III, who is reported to have taken part in the 897 synod, became pope in 904 and reaffirmed the condemnation of Formosus, again calling ordinations into question.

Legacy

Between the death of Formosus in 896 and the election of Sergius III in 904, nine popes held office, several dying violently. The 10th-century papacy that followed, dominated by the Roman family of Theophylact and his daughter Marozia, was later called the “pornocracy” by critics and the saeculum obscurum, or “dark age”, by the 16th-century church historian Cardinal Caesar Baronius.

The main legal charge against Formosus soon lost its force. Rules against moving a bishop from one see to another had been taken seriously in the early church, but Marinus I, elected in 882, had already been bishop of Caere before becoming pope, and from the 10th century onward it became normal for bishops of other dioceses to be elected to Rome. By modern times the charge that had justified the trial was simply obsolete.

The Cadaver Synod became the most notorious example of this period. Reform movements of the following century, including monasteries such as Cluny and the reforming popes of the 11th century, sought to free the church from the control of local aristocrats.

The scene has fascinated later artists and writers. The French painter Jean-Paul Laurens depicted it in 1870 in a dramatic canvas showing the enthroned corpse facing Stephen VI across an empty hall.

Timeline

• 866: Formosus leads a papal mission to Bulgaria.
• 876: Pope John VIII excommunicates Formosus.
• 883: Pope Marinus I restores Formosus as bishop of Porto.
• 891, October: Formosus is elected pope.
• 896, February: Formosus crowns Arnulf of Carinthia emperor.
• 896, 4 April: Death of Formosus.
• 896, May: Election of Stephen VI after the brief reign of Boniface VI.
• 897, January: The Cadaver Synod in the Lateran Basilica.
• 897, summer: Stephen VI is deposed and strangled.
• 898: John IX annuls the synod and bans trials of the dead.

Why it matters

The Cadaver Synod shows how far the papacy had fallen under the control of rival Italian factions after the Carolingian collapse. Its shock helped shape the later demand for church reform and remains one of the strangest episodes in the history of the papacy.