FORMOSO, PAPA. — Perhaps a native of Rome. In 864 or 865, Niccolò I (858–67) made him cardinal-bishop of Porto, and in the autumn of 866 sent him with Paolo di Populonia to the Bulgarians to promote their conversion. He was so successful that their king, Boris, requested him as archbishop.
Toward the end of 867, F. was recalled to Rome, where he was held in high esteem also by Pope Adriano II (867–72). But his successor, Giovanni VIII (872–82), who regarded him as a personal enemy, after entrusting him with confidential assignments during the early years (Jaffé-Wattenbach, 2018), subsequently placed him under accusation, believing that he had proof of schemes undertaken by F. against the Curia. F. fled Rome, and a Synod then excommunicated and deposed him (19 April 876); the condemnation was renewed at the Councils of Ponthion (June 876) and Troyes (August 878). On 14 September the Pope admitted him to lay communion, on condition that he never set foot in Rome again. Instead, Marino I (882–84) absolved him, and his successor Adriano III (884–85) restored to him his former see of Porto. In 885 F. consecrated the new pope Stefano V (885–91), whom he succeeded on 19 September 891. In the Photian controversy he adopted an attitude of extreme rigor (Jaffé-Wattenbach, 2478); he declared himself in favor of the union of the see of Bremen with Hamburg (ibid., 3483, 3487, 3488); he supported the Carolingian Carlo against Eudes (ibid., 3490–94). On 30 April 892 he crowned Lamberto of Spoleto emperor, as associate of his father, Guido. But soon, in opposition to the Spoletans, he summoned Arnolfo of Carinthia to Italy and crowned him emperor (22 April 896). He died on 4 April 896, in time not to see the Spoletans become masters of Rome once more. Their vengeance was fierce. In January 897, F.’s corpse, exhumed from the tomb where it had rested for nine months, was brought before a Synod presided over by Stefano VI (896–97) and subjected to a formal trial. His election having been declared null, his acts illegitimate, and his ordinations invalid, he was buried in a common grave, from which the mob removed him in order to throw him into the Tiber.