Cadaver Synod

The Cadaver Synod (also called the Cadaver Trial; Latin: Synodus Horrenda) is the name commonly given to the posthumous ecclesiastical trial of Pope Formosus, held in the Basilica of St. John Lateran in Rome during January of 897. The trial was conducted by the successor, Pope Stephen VI (sometimes called Stephen VII), to Formosus' successor, Pope Boniface VI. Stephen accused Formosus of perjury and of having acceded to the papacy illegally. At the end of the trial, Formosus was pronounced guilty and his papacy retroactively declared null.

The Cadaver Synod and related events took place during a period of political instability in Italy. This period, which lasted from the middle of the 9th century to the middle of the 10th century, was marked by a rapid succession of pontiffs. Often, these brief papal reigns were the result of the political machinations of local Roman factions, about which few sources survive.

Formosus became bishop of Porto in 864 during the pontificate of Pope Nicholas I. He carried out missionary activity among the Bulgarians, and was so successful that they requested him for their bishop. Nicholas refused his permission, because an appointment in Bulgaria would require Formosus to leave his see in Porto, and the fifteenth canon of the Second Council of Nicaea forbade a bishop to leave his own see to administer another.

In 875, shortly after Charles the Bald's imperial coronation, Formosus fled Rome in fear of then-pope John VIII. A few months later in 876, at a synod in Santa Maria Rotunda, John VIII issued a series of accusations against Formosus and some of his associates. He asserted that Formosus had corrupted the mind of the Bulgarians "so that, so long as [Formosus] was alive, [they] would not accept any other bishop from the apostolic see," that he and his fellow conspirators had attempted to usurp the papacy from John, and finally that he had deserted his see in Porto and was conspiring "against the salvation of the state and of our beloved Charles [the Bald]." Formosus and his associates were excommunicated.

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