Pope Victor III (c.1026 – 16 September 1087), born Daufer (Dauphar), Latinised Dauferius, was the Pope (from 24 May 1086) as the successor of Pope Gregory VII, yet his pontificate is far less impressive in history than his time as Desiderius, the great Abbot of Monte Cassino.
Somewhat later Desiderius attached himself to the Court of Victor II at Florence and there met two monks of the renowned Benedictine monastery of Monte Cassino, with whom he returned to their monastery in 1055. He joined the community, and was shortly afterwards appointed superior of the dependent house at Capua. In 1057, Stephen IX (X) who had retained the abbacy of Monte Cassino came thither and at Christmas, believing himself to be dying, ordered the monks to elect a new abbot. Their choice fell on Desiderius. The pope recovered, and, desiring to retain the abbacy during his lifetime, appointed the abbot-designate his legate for Constantinople. It was at Bari, when about to sail for the East, that the news of the pope's death reached Desiderius. Having obtained a safe-conduct from Robert Guiscard, the Norman Count (later Duke) of Apulia, he returned to his monastery and was duly istalled by Cardinal Humbert on Easter Day, 1058. A year later Pope Nicholas II (1059–61) raised him to the cardinalate, in 1059, as Cardinal-Priest with the ancient cardinal title of S. Cecilia and he received the abbatial blessing.
Desiderius was the greatest of all the abbots of Monte Cassino with the exception of the founder, and as such won for himself "imperishable fame" (Gregorovius). He rebuilt the church and conventual buildings, established schools of art and re-established monastic discipline so that there were 200 monks in the monastery in his day. On 1 October 1071, the new and magnificent Basilica of Monte Cassino was consecrated by Pope Alexander II. Desiderius's great reputation brought to the abbey many gifts and exemptions. The money was spent on church ornaments of which the most notable were a great golden altar front from Constantinople, adorned with gems and enamels and "nearly all the church ornaments of Victor II which had been pawned here and there throughout the city" [Chron. Cass., III, 18 (20)]. The bronze and silver doors of the Cassinese Basilica which Desiderius erected remain, and in the Church of S. Angelo in Formis, near Capua, some of the frescoes executed by his orders may still be seen. Peter the Deacon gives (op. cit., III, 63) a list of some seventy books which Desiderius caused to be copied at Monte Cassino, including works of Saint Augustine, Saint Ambrose, Saint Bede, Saint Basil, Saint Jerome, Saint Gregory of Nazianzus and Cassian, the registers of Popes Feliz and Leo, the histories of Josephus, Paul Warnfrid, Jordanus and Saint Gregory of Tours, the "Institutes" and "Novels" of Justinian, the works of Terence, Virgil and Seneca, Cicero's "De natura deorum", and Ovid's "Fasti".
Desiderius had been appointed papal vicar for Campania, Apulia, Calabria and the Principality of Beneventum with special powers for the reform of monasteries; so great was his reputation with the Holy See that he "was allowed by the Roman Pontiff to appoint Bishops and Abbots from among his [Benedictine] brethren in whatever churches or monasteries he desired of those which had been widowed of their patron" (Chron. Cas., III, 34).
Within two years of the consecration of the Cassinese Basilica, Alexander II died and was succeeded by Hildebrand as Pope Gregory VII. The chief importance of Desiderius in papal history lies in his influence with the Normans, which he was able repeatedly to exert in favour of the Holy See. Already in 1059 he had persuaded Robert Guiscard and Richard of Capua to become vassals of St. Peter for their newly conquered territories: now Gregory VII immediately after his election sent for him to give an account of the state of Norman Italy and entrusted him with the negotiation of an interview with Robert Guiscard on 2 August 1073, at Benevento. In 1074 and 1075 he acted as intermediary, probably as Gregory's agent, between the Norman princes themselves, and even when the latter were at open war with the pope, they still maintained the best relations with Monte Cassino (end of 1076). At the end of 1080 Desiderius obtained Norman troops for Gregory. In 1082 he visited the (then Italian king and future Holy Roman) Emperor Henry IV at Albano, while the troops of the Imperialist antipope were harassing the pope from Tivoli. 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. In 1084 when Rome was in Henry's hands and the pope besieged in Sant' Angelo, Desiderius announced the approach of Guiscard's army to both emperor and pope.
(Under pressure from Prince Jordan I of Capua (to whom also he had rendered important service), he was elected on 24 May 1086, taking the throne name of Victor III, but and after his tardy consecration, which did not take place until 9 May 1087, owing to the presence of the antipope Victor III's stay in Rome was short.) After celebrating Easter in his monastery Victor proceeded to Rome, and when the Normans had driven the soldiers of the Antipope Clement III (Guibert of Ravenna) out of St. Peter's, was there consecrated and enthroned (9 May 1087). He only remained eight days in Rome and then returned to Monte Cassino, though with the help of Matilda and Jordan, he took back the Vatican Hill. Before May was out he was once more in Rome in answer to a summons for the countess Matilda of Tuscany, whose troops held the Leonine City and Trastevere, but when at the end of June the antipope once more gained possession of St. Peter's, Victor again withdrew at once to his Monte Cassino abbey. In August a council or synod of some importance was held at Benevento, which renewed the excommunication of the antipope Clement III and the condemnation of lay investiture, proclaimed a kind of crusade against the Saracens in northern Africa and anathematised Hugh of Lyons and Richard, Abbot of Marseilles. When the council had lasted three days, Victor became seriously ill and retired to Monte Cassino to die. He had himself carried into the chapter-house, issued various decrees for the benefit of the abbey, appointed with the consent of the monks the prior, Cardinal Oderisius, to succeed him in the abbacy, just as he himself had been appointed by Stephen IX (X), and proposed Odo of Ostia to the assembled cardinals and bishops as the next pope. He died on 16 September 1087, and was buried in the tomb he had prepared for himself in the abbey's chapter-house. His successor was Pope Urban II (1088–99).
For Desiderius's relations with the Normans