Pope Sergius III: Murder, Scandal, and the Dark Age of the Papacy

If the story of Pope Stephen VI and the Cadaver Synod seems like the moment the medieval Papacy reached rock bottom, Pope Sergius III offers an uncomfortable counterargument.

His reign has nearly everything you could ask for in a medieval political thriller: disputed elections, imprisoned popes, allegations of murder, aristocratic power brokers, a bitter feud over the corpse of a dead pontiff, and an alleged affair that may have produced another pope.

The real problem is that some of the best stories about Sergius III may not be true.

Sergius ruled from 904 to 911, during one of the most chaotic periods in the history of the medieval Papacy. Roman noble families fought for control of the city and the papal throne. Popes were disposable, old political grudges remained alive, and the dispute surrounding Pope Formosus continued to influence Roman politics years after his death.

Sergius was one of Formosus’s fiercest opponents, had attempted to become pope once before, and returned to Rome backed by powerful aristocratic allies.

Many surviving accounts of Sergius were written by his political enemies or by later chroniclers eager to portray tenth-century Rome as a cesspool of corruption. Modern works caution that the narrative sources for Sergius’s life are deeply partisan.

Early Life

Sergius was born in Rome. His father, Benedictus, is believed to come from a noble Roman family. Little else is known about his early years.

He entered the Church at a young age and became part of the Roman clergy. Around 893, Pope Formosus consecrated Sergius as Bishop of Caere, possibly in an effort to remove him from Rome.

When Formosus died in 896, the Roman Church was divided into bitter political factions. One side supported the late pope and his policies. The other regarded his elevation to the papacy as unlawful and sought to undo his actions.

Sergius became one of the leading members of the anti-Formosan faction.

The dispute soon produced one of the strangest events in papal history.

In 897, Pope Stephen VI ordered Formosus’s corpse exhumed from its tomb, dressed in papal vestments, seated upon a throne, and subjected to a formal trial. The proceedings became infamous as the Cadaver Synod.

Formosus was found guilty. His papacy was declared invalid, his ordinations were annulled, and his corpse was stripped of its vestments. The three fingers he had used to perform blessings were cut from his right hand.

The spectacle horrified many Romans. Stephen VI was overthrown and eventually strangled in prison.

Rise to the Papacy

Sergius first attempted to claim the papacy in 898.

Following another contested election, his supporters put him forward against John IX. John ultimately prevailed with the support of Emperor Lambert of Spoleto. Sergius and several of his leading supporters were condemned, deposed, and excommunicated.

Over the next several years, the papal throne became dangerously unstable. John IX died around 900 and was followed by Benedict IV. After Benedict’s death came Leo V, whose pontificate lasted only a few weeks before he was overthrown and imprisoned by a Roman cleric named Christopher.

Christopher then took the papal throne himself. His reign lasted fewer than three months, and he is generally regarded as an antipope rather than a legitimate successor to Leo V.

In early 904, Sergius returned from exile backed by the powerful Alberic I of Spoleto and other supporters. Sergius entered Rome, overthrew Christopher, and finally obtained the office he had failed to secure six years earlier.

On 29 January 904, Sergius III was consecrated pope.

Then comes the first great mystery of his reign.

What happened to Leo V and Christopher?

According to some accounts, both men were strangled in prison on Sergius’s orders. The accusation has followed Sergius for more than a thousand years, and some modern reference works continue to report their deaths as executions connected with his seizure of power.

Other sources say Christopher was sent to a monastery rather than murdered. The most explicit accusation that Sergius had both Leo and Christopher strangled comes from Eugenius Vulgarius, a writer involved in the bitter Formosan controversy.

Sergius may have ordered the deaths of his rivals.

Or he may have inherited a reputation created by his enemies.

We’ll never know for certain.

Papacy

The Ghost of Formosus Returns

Whatever uncertainty surrounds the murder accusations, Sergius’s hostility toward Pope Formosus is far better documented.

Popes Theodore II and John IX had worked to rehabilitate Formosus after the Cadaver Synod. John IX formally overturned the proceedings against him and upheld the validity of his ordinations.

Sergius called a new synod and reversed those decisions.

Sergius reaffirmed the anti-Formosan position and declared ordinations performed by Formosus invalid. Clergymen who had received their orders from Formosus could therefore be required to undergo ordination again.

The consequences were potentially enormous.

A bishop consecrated by Formosus might already have ordained priests or consecrated other bishops. If Formosus’s own ordinations were invalid, how far down the chain did the problem extend?

The result was confusion, controversy, and a furious theological debate. Writers such as Auxilius of Naples defended the validity of Formosus’s ordinations and attacked Sergius’s policies.

For centuries, Sergius was sometimes accused of ordering Formosus’s corpse exhumed yet again and subjected to another condemnation before having the body beheaded.

The story may be the result of later confusion between Sergius III and Stephen VI. There is no good evidence that Sergius staged a second Cadaver Synod.

His campaign against Formosus was political and ecclesiastical enough without dragging the unfortunate corpse back into court.

The Rise of Rome’s Powerful Families

Sergius’s return also signaled a major shift in Roman politics.

Behind him stood members of a rising aristocratic network centered on Theophylact, his wife Theodora, and eventually their daughter Marozia.

Theophylact held important positions within Rome and the papal administration. Under Sergius, his influence grew considerably. The family would become one of the dominant forces in Roman politics during the first half of the tenth century, helping determine who could obtain, hold, and sometimes lose the papal throne.

This period is often associated with the Saeculum Obscurum, the “Dark Age” of the Papacy. Later writers portrayed it as an era in which Roman aristocrats effectively captured the papal office and used it as another prize in their struggles for political dominance.

Marozia and the Papal Sex Scandal

Marozia would become one of the most powerful women in tenth-century Rome.

According to the later chronicler Liutprand of Cremona, who was deeply hostile toward the Roman aristocracy, Sergius III had an affair with the young Marozia. Their relationship allegedly produced a son who eventually became Pope John XI.

If true, the implications are extraordinary: a pope fathered an illegitimate son with a Roman noblewoman, and that son later became pope himself.

The story became one of the defining scandals of the medieval Papacy.

It is also disputed.

John XI was certainly Marozia’s son. Both Liutprand and a notice preserved in the Liber Pontificalis identify Sergius as his father, but other evidence leaves open the possibility that John was the son of Marozia’s husband, Alberic I of Spoleto. Modern scholarship treats Sergius’s paternity as possible but not certain.

Liutprand is particularly difficult as a source.

He wrote decades after Sergius’s death and had no affection for the Roman aristocracy he described. His account is colorful, memorable, and frequently hostile.

Auxilius of Naples and Eugenius Vulgarius, both contemporaries of Sergius and hostile toward him, never mention the alleged affair or the claim that Sergius fathered John XI.

It makes for a great story, but the evidence is muddled with rumor and uncertainty.

Rebuilding Rome

For all the scandal attached to his name, Sergius did more than fight dead popes and Roman rivals.

One of the clearest physical accomplishments of his pontificate was the restoration of the Lateran Basilica.

The church had been badly damaged during the political turmoil and natural disasters of the preceding years. Sergius undertook a major restoration of the building, which remained the cathedral church of the Bishop of Rome and one of the most important churches in Christendom.

He also intervened in church affairs outside Rome, protected the interests of Archbishop John of Ravenna, and confirmed ecclesiastical foundations and privileges.

These actions rarely receive as much attention as the accusations of murder and sexual scandal, but they serve as an important reminder that even during Rome’s political chaos, the normal machinery of the medieval Church continued to function.

A Fourth Marriage and Trouble with Constantinople

Sergius also became involved in a controversy hundreds of miles from Rome.

Byzantine Emperor Leo VI desperately needed a male heir. After losing three wives, he married Zoe Karbonopsina, who had already given birth to his son, the future Constantine VII.

There was one major problem. It was Leo’s fourth marriage.

The Byzantine Church strongly opposed fourth marriages, regarding them as forbidden and deeply contrary to its canonical tradition. Patriarch Nicholas Mystikos refused to accept the emperor’s actions, so Leo turned to Rome for support.

Sergius gave his support to Leo and recognized the marriage.

In the Latin West, a fourth marriage did not face the same canonical prohibition found in Byzantine practice. Sergius’s position therefore placed Rome on the emperor’s side in a bitter ecclesiastical dispute and contributed to further tension with Constantinople.

The episode is easy to overlook, but it shows that Sergius’s papacy was not concerned solely with Roman factional warfare. Even during one of the most unstable periods in papal history, the pope remained involved in disputes stretching across the Christian world.

Death and Legacy

Sergius III died on 14 April 911, after ruling for a little more than seven years.

Compared with many popes immediately before him, seven years was practically an eternity.

He was buried in St. Peter’s Basilica.

Sergius became one of the most notorious popes of the early Middle Ages. He has been accused of murdering his predecessors, fathering a future pope, overturning legitimate ordinations, and surrendering the papacy to Rome’s aristocratic families.

Some of those accusations rest on solid evidence. Others do not.

His renewed attack on Formosus is undeniable. His dependence upon powerful Roman aristocrats is clear. His seizure of the papacy came through political force rather than anything resembling a peaceful ecclesiastical election.

But the murders of Leo V and Christopher remain uncertain, and his alleged affair with Marozia cannot be established beyond doubt.

Even the sources themselves reveal how difficult this period is for historians.

Auxilius regarded Sergius as a criminal. Eugenius Vulgarius initially attacked him but later wrote more favorably about him. Liutprand of Cremona, writing decades later, helped immortalize some of the most sensational accusations. Modern scholarship is forced to reconstruct Sergius’s reign from these conflicting and deeply partisan accounts.

Conclusion

Pope Sergius III ruled at a moment when the medieval Papacy was struggling to survive its own internal politics.

The imperial protection that had once surrounded Rome had weakened. Powerful aristocratic families increasingly dominated the city. Rival factions fought over papal elections, and the controversy surrounding Formosus had transformed theological questions into weapons of political revenge.

Sergius was both a product of that world and one of its major participants.

He returned from political defeat to seize the papal throne. He revived the campaign against Formosus. He allied himself with the family that would dominate Roman politics for decades. And whether deserved or not, his name became permanently linked with murder, sexual scandal, and corruption.

In the shadowy world of tenth-century Rome, reputation could be as deadly as reality. And few medieval popes emerged from the period with a darker reputation than Sergius III.

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