Leader of the Normans in Italy, born about 1015 near Coutance (Normandy) and died in 1085. Son of Tancred of Hauteville, belonged to one of the most powerful Norman families arrived in Italy in the first decades of the 11th century. In Italian lands, Norman warriors acted on principle as mercenaries in the service of the Lombard Princes or Byzantine Governors of the Greek provinces of the South of the peninsula. As payment for his work, some lineages, including the Hauteville, got honours and lands. Roberto Guiscardo soon became head of his family, and was at the forefront of the Normans when they went on to develop a policy of conquest self-serving. Guiscardo was able to take advantage of internal rivalries among the Lombard Duchies and between these and the Byzantine States in Naples, Amalfi and Gaeta.
In 1042 Guiscardo undertook the conquest of the Duchy of Apulia, which would not end until 1060. The Pope Leo IX, faced with the threat of his advance on Rome, presented the army Norman in 1053, battle was defeated and taken prisoner. But both the Pope and Guiscard soon realized the advantages of a mutual Alliance. The Norman freed the Pontiff and paid vassalage, offering military support to the Papal States. In return, León IX recognized the domain Norman on the already conquered territories and offered to Guiscardo possession of the Lombard Duchies and the Byzantine provinces. His successor in the Papacy, Nicolás II, faced the Roman aristocracy as well as the German Emperor, requested the aid of the Normans. In 1059, in Melfi, Roberto Guiscardo and the Pope concluded an Alliance of mutual support. The Norman renewed their fidelity to the Pope. This in turn appointed him Duke of Apulia and Calabria and confirmed the domain on its present and future conquests. For his part, Guiscardo pledged to return the Byzantine territories into obedience to the Roman Church. These agreements were confirmed in the following pontificates by Alejandro II and Gregory VII. While relations between the Popes and Guiscardo were often difficult, this Alliance was never to break.
From 1059 Guiscardo undertook a series of conquests that put an end to the Byzantine domain in the South of Italy and the Muslim in Sicily. The process of conquest was slow. In 1059 Normans conquered Reggio. In 1062, they took Brindisi and between 1060 and 1070, completed the conquest of Calabria and Campania. The city of Bari fell under Norman domination in 1071. In 1073 Guiscardo Salerno, conquered Gaeta and 4 years later with what the ancient Greek provinces were definitely ragged of Byzantium. The domain Norman of southern Italy was completed with indirect control over Amalfi and Naples, which at the beginning of the 12th century would be definitely annexed by the Norman Roger II.
From its continental bases, the Normans were launched in the conquest of Sicily. The campaign, led by Guiscard's brother, Roger, was long and difficult because of the resistance of Islamized chiefs of the island and to the small number of Norman and Italian fighters who took part in the conquest.
Roger won Messina in 1061, at 1070 Palermo and Trapani in 1078. The conquest would not conclude until 1091, because dead Roberto Guiscardo, and assumed the reintegration of the island to the Christian West and the beginning of the decline of the domino Muslim on the Western Mediterranean. Another of Norman expansion fronts were the Byzantine territories in the eastern shores of the Adriatic.
In 1071 Guiscardo fielded a fleet which threatened the shores of Illyria, but did not come into action to arrange a marriage agreement between his daughter and a son of the Byzantine Emperor Miguel IV. After his death, and taking advantage of the instability that had created the ascension of the new dynasty of the Komnenos on the throne of Byzantium, Guiscardo undertook a new offensive. In 1081 he/she landed on the shores of Illyria, with the blessing of the Holy See. The Venetians, allies of the Byzantines, defeated the Norman fleet, but the terrestrial campaign of Guiscard advanced without difficulty. The Norman army conquered Durazzo and thence was interned in Epirus, moving toward Macedonia and Thessaly, where laid siege to the city of Larisa (1084). At that time there was an insurrection against Norman rule in the South of Italy, at the time that Pope Gregorio VII sought the help of Guiscardo against the Emperor Henry IV, that it threatened Rome. His son Bohemond was at the head of the army in Thessaly, but the local resistance, the presence of the Emperor Alejo I in the area, and the reconquest of Durazzo by the Venetians forced the Normans to return to Italy. Guiscardo went to the aid of the Pope, who had been deposed and imprisoned by Enrique IV. The Norman it sacked Rome and freed the Pontiff from his prison in the castle of Sant'Angelo, leading him to his domain of Salerno. From there, Guiscardo resumed the offensive against the Byzantines. He/She defeated a fleet of Greeks and Venetians in Corfu, but could not continue their advance towards Constantinople, died in 1085 victim of an epidemic that decimated his army.
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