There was at Durazzo a distinguished man who had come from Venice, called Domenico. He hated another man, said to be the son of the Doge of Venice, because he himself was not allowed to be part of his council, entry to which was given to many other people there.  Domenico sought to deprive him of his command. He summoned one of the deserters to him, a man from Bari who was dear to him and in whose good faith he trusted. He instructed him to go to Robert’s camp by night and inform the duke that he wished to reveal to him certain things to his advantage, and tell him to  come to a place called Petra, which was near the church of St. Nicholas. Robert went there with a small escort. [Meanwhile] the deserter had returned and summoned the Venetian, who came to the duke and promised that he could easily surrender Durazzo  to him if the latter would give him what he sought. The duke swore on oath to grant him what he wanted and to give him his niece in marriage. Both went home in secret after this meeting, having previously decided  when the duke would return and Domenico then hand the city over to him.
When the day that they had both decided upon came, the duke chose the men of Cosenza, whom he knew to be fleet of foot, and to accompany them some picked knights,  then in the stillness of the night he marched on the town. He took the precaution of sending the deserter on ahead, to tell him from the town what needed to be done. The Venetian had been watching for him for much of the night and had fallen asleep, but the Bariot deserter  promptly woke him up and told him of the duke’s arrival. The Venetian told him to bring his trusted men into the city, and not to be afraid. The messenger returned and had the duke’s infantry go in first, and to them he handed over the walls of the tower, which was unguarded.  During the night they made not a sound. At daybreak the whole town realised from all sorts of noise that their enemies had gained entry. All the Venetians seized their weapons,  except those whom the fifth columnist had brought over to Robert’s side. With their enemies on the ramparts all the inhabitants dug a ditch inside the walls, to make it difficult for the enemies to climb down into the city. The duke had ordered his troops to leave camp on the double. When he heard their voices he ran to them, and despatched them through every gate.  Seeing themselves attacked both from within and without the inhabitants loudly denounced the treachery of the Venetians, and as a result the whole Venetian garrison fled. Some were killed, others captured, while some of them fled to the sea, boarded their ships and thus escaped across the Adriatic.  Every Venetian who stayed to fight was made prisoner during the city’s capture, including the Doge’s son, while their fleet sailed away. So the duke secured Durazzo for himself. Being unable to conquer it by force of arms alone, he secured victory through a stratagem. The Venetian rejoiced, because after the surrender everything that had been  promised to him was fulfilled.
Meanwhile the people of Troia and Ascoli revolted, the former refusing to pay the customary tribute, the latter lamenting the destruction of their walls. They combined together to attack Roger,  the duke’s noble heir, who was distinguished for his good sense and skill at arms. Trapped in the citadel at Troia, he defended himself as best he could, until at last some of his and his father’s allies hurried to his aid. Leaving the citadel  he threw himself furiously on the rebellious townspeople and inflicted all sorts of punishments upon them. He had one man’s hand cut off, and another’s foot, a third lost his nose, another his testicles; he deprived other men of their teeth or ears. Thus a captive tigress is accustomed to hide her anger while she is a prisoner and unable to give vent to her rage,  but if she happens to break out of her cage and escape then she shows a quite unusual fury, seizing and devouring all whom she sees. Even a lion avoids the ferocious beast, although she is the smaller and he the stronger of the two.
Robert returned to Apulia once more after a year away, crossing the Adriatic with two ships,  and entrusting his men to his eldest son, called Bohemond, and Brienne. Learning that Cannae had rebelled against him the duke besieged it,  and after its capture he raised it to the ground. Herman had ruled this town. He was born of the same mother as Abelard, son of Humphrey, but they did not however share the same father. Both brothers were distinguished soldiers, but they both yielded to the power of Robert,  to whom scarcely anyone in the world was equal.
After the destruction of Cannae, he set out for Rome against Henry, the enemy of Gregory, the Roman pontiff. Henry had been besieging the city for some two years with a great crowd of barbarians. He had breached the high walls with his stonethrowers  and destroyed many of the undaunted city’s towers. The Trastevere district had already surrendered to him, and Gregory was trapped in a citadel that was however well-protected. Indeed so excellently was it constructed that it was impregnable,  and the pope had provided it with a faithful garrison.
When King Henry learned of the great army  with which Robert was preparing to march against him, he fled, terrified of the duke’s bravery and power, already renowned throughout the world. Fearing to wait for him he retreated to safety. Robert hastened to Rome and stormed the walls of that famous city, with the aid of just a few of Gregory’s partisans.  He fired some of the buildings, violently freed the pope who had been under siege for so long, and brought him most honourably back with him to Salerno. After the duke’s departure  the greedy citizens yielded once again to Henry. He had given to them as pope Guibert of Ravenna, a man who had wickedly risen up against the Holy Father and dared to seize the Apostolic See, being known by the mob as Clement. Returning to Salerno from the city of Romulus the duke dismissed his troops. Never had he possessed an army such as this for  he had led to Rome six thousand knights and thirty thousand infantry. So it was that he defeated at one and the same time the world’s two greatest rulers, the German king and mighty ruler of the Roman Empire.  The latter had rushed to battle and there had been conquered, the other had been overcome merely by fear of his [Guiscard’s] reputation.
 The Doge of Venice was also Domenico Silvio.
 The son of the Doge was defeated by Guiscard in the naval engagement off Corfu in 1085.
 Petra is today Shkamm or Sasso Bianco.
 According to Malaterra [Book III], Guiscard promised Domenico the daughter of his brother William of the Principate.
 The resistance by the citizensh of Durazzo lasted three days according to Malaterra after which they surrendered.
 A conspiracy developed in the two towns in the absence of Guiscard, an action possible provocked by the intrigues of Alexius. He had written to Herman de Cannae in June 1081 encouraging him to rebel against Guiscard.
 The constable Brienne.
 Herman de Cannae, brother of Abelard and nephew of Guiscard. He had been a hostage in Constantinople in 1064, rebelled in 1073 with Peter de Trani and freed from captivity at the beginning of 1076. He later seems to have been reconciled with Guiscard’s sons and accompanied Bohemond on the First Crusade.
 Humphrey de Hauteville had married the sister of the duke of Sorrento.
 The Castel San Angelo.
 Gregory had been besieged in Rome since October 1081 and had long called for Robert’s assistance. In 1083, Henry had occupied the Transtevere district and the pope was shut up in the Castel San Angelo.
 On 21st May 1084, Henry IV, told by Desiderius of Montecassino of the imminent arrival of Guiscard, left Rome. Guiscard freed Gregory and burned the city from the Lateran to the Castel San Angelo. Cowdrey, H. E. J., The Age of Abbot Desiderius: Montecassino, the Papacy and the Normans in the Eleventh and Early Twelfth Centuries, (Oxford University Press), 1983 is the best study of Desiderius. The chief source is the Chronicon Cassinense, in Mon. Germ. Hist.: Script., vol. VII, reprinted in Patrologia Latina, vol. 173; some autobiographical details can be found in his own Dialogues in Patrologia Latina, vol. 149. Ibid, Mann, H. R., The Lives of the Popes, vol. vii, pp. 218-244 remains useful.
 Born c.1025 of noble birth in Parma in Lombardy, Guibert served at the German court (c. 1054-1055) and became imperial chancellor for Italy (1058-1063). As such he supported the election of Bishop Peter Cadalus of Parma as antipope Honorius II (1061). His appointment by Henry IV of Germany as archbishop of Ravenna was confirmed by Pope Alexander II (1073), but he later clashed with Alexander’s successor, Gregory VII. When Guibert became the Italian leader of the imperialist faction opposing the Gregorian reform, Gregory excommunicated him. He was elected antipope on June 25th 1080, by a synod called by Henry at Brixen, which declared Gregory deposed. He was enthroned when Henry finally seized Rome (March 24th 1084), and on March 31st he crowned Henry emperor. Clement remained antipope throughout the succeeding pontificates of Victor III and Urban II and died September 8th 1100.
 Guiscard and Gregory arrived back in Salerno at the end of June 1084.
 This double victory over Alexius Comnenus and Henry IV became legendary in the literature of the eleventh and twelfth centuries.