Adelchis, who had imprisoned the emperor while Lambert was staying in Benevento, released his captive to lead the forces against the infidels.
The free emperor immediately deposed Lambert from his imperial position and replaced him with Suppo III, a cousin of his wife Engelberga.
After his death, he was replaced as emperor by his uncle Charles the Bald, who reappointed Lambert to his old post in Spoleto (February or June 876).
He also appointed Lambert's younger brother Guy as margrave of Camerino with the job of protecting the pope.
On 16 July, at Ponthion, Charles confirmed the donation of a large part of Spoletan territory to the papacy, but Lambert was still the most powerful lord in the central peninsula and a practically independent prince.
At Troyes, he held a synod in which he offered to crown Louis the Stammerer emperor, adopted Boso of Arles as his son, and excommunicated his Italian enemies (Lambert and Adalbert).
The pope even accused Lambert of desiring the imperial crown for himself, which is probable considering the subsequent history of his dynasty.