Pope Formosus died in April 896 after a turbulent five-year pontificate entangled in the power struggles between rival claimants to the imperial crown. His successor-but-one, Pope Stephen VI, owed his position to the Spoletan faction that Formosus had betrayed by crowning the Carolingian Arnulf of Carinthia as emperor.
In January 897, Stephen convened a synod in the Lateran basilica and had Formosus exhumed. The corpse — dead approximately nine months — was dressed in full papal vestments and propped on a throne to face trial.
The trial
The charges: that Formosus had committed perjury, had coveted the papacy, and had violated canon law by transferring from the bishopric of Porto to the see of Rome — bishops were then forbidden to change sees. A deacon was appointed to stand beside the corpse and answer on its behalf. Stephen reportedly screamed the accusations directly at the body.
The verdict was never in doubt. Formosus was convicted on all counts. His papacy was declared null, all his acts and ordinations invalidated, and the three fingers of his right hand — the fingers of benediction — were hacked off. The corpse was stripped of its vestments, reburied in a common grave, then dug up again and thrown into the Tiber.
The aftermath
The spectacle disgusted Rome. A monk reportedly recovered the body from the river. Within months an uprising deposed Stephen VI; he was imprisoned and strangled in the summer of 897.
His successor Theodore II — pope for roughly twenty days — annulled the synod, rehabilitated Formosus, and had the body reburied in St Peter’s in full vestments. Pope John IX then formally prohibited any future trial of a dead person.
The matter did not rest. Sergius III (904-911), who had participated in the original synod as a bishop, reaffirmed the conviction upon becoming pope and reportedly had a flattering epitaph inscribed for Stephen VI. Later popes quietly let the reinstatement of Formosus stand.
The Cadaver Synod marked the beginning of the papacy’s darkest institutional stretch — the period historians once called the “pornocracy” — roughly six decades in which the office changed hands by murder, bribery, and family intrigue.