Pope Victor III - Wikipedia
At about Easter 7 the bishops and cardinals assembled at Rome summoned Desiderius and the cardinals who were with him at Monte Cassino to come to Rome to treat concerning the election. In 1083 the peace-loving abbot joined Hugh of Cluny in an attempt to reconcile pope and emperor, and his proceedings seem to have aroused some suspicion in Gregory's entourage. Odo was duly elected his successor as Pope Urban. He was the successor.
When autumn came, Desiderius accompanied the Norman army on its march to Rome. Desiderius had been appointed papal vicar for Campania, Apulia, Calabria and the Principality of Beneventum with special powers for the reform of monasteries. Maurum" and letters to King Philip I of France and to Hugh of Cluny, which no longer exist. In 1084, when Rome was in Henry's hands and the pope besieged in Castel Sant'Angelo, Desiderius announced the approach of Guiscard's army to both emperor and pope.
The only literary work of his that remains is his "Dialogues" on the miracles performed. It was a decision that his mother vehemently opposed, owing to his being the only son and the only child.