In January 897, Pope Stephen VI convened the so-called Cadaver Synod, exhuming the nine-months-dead body of Pope Formosus, propping it on a throne, and putting it on trial for alleged violations of church law. The corpse was found guilty, stripped of its vestments, mutilated, and thrown into the Tiber River, one of the strangest episodes in papal history and a symptom of the era's brutal power struggles.
Formosus had been a controversial pope, entangled in the messy politics of the Carolingian succession, and his death in 896 did not end the disputes he'd inflamed. Pope Stephen VI, aligned with rival factions, decided the dead pope still needed to answer for his supposed crimes: violating canon law by accepting the papacy after previously being excommunicated, among other charges.
In a scene almost unbelievable in its grotesquerie, Formosus's body was disinterred, dressed in full papal regalia, and seated on a throne in the synod hall. A young deacon was assigned to speak on the corpse's behalf, answering the tribunal's questions in the first person as if channeling the dead man. Unsurprisingly, the corpse was convicted.
Stephen ordered the fingers used for consecration hacked off, stripped the vestments, and had the body dumped in the Tiber, only for it to be recovered, according to legend, by a monk who saw it wash ashore. Public revulsion at the spectacle helped fuel a backlash; Stephen VI was imprisoned and strangled later that year, and a subsequent pope annulled the whole grotesque trial.