Robert Guiscard, the founder of the kingdom of Naples, born about 1015, died July 17, 1085. His father, Tancred de Hauteville, a petty Norman baron, had twelve sons, of whom Robert was the sixth. As the paternal estate was insufficient to support so large a family, the three eldest sons went to Italy, where they secured rich possessions in the Norman colony of Apulia, of which they eventually became the leading nobles. Attracted by their success, the younger brothers also went to Italy, and Robert, who was surnamed Guiscard, the prudent or adroit, showed so much valor and address that on the death of his brother Humphrey in 1057 he was proclaimed count of Apulia, to the exclusion of the young son of the latter. He soon after overran Calabria, and received from Pope Nicholas II. the title of duke of both provinces, with the additional grant of whatever portions of Italy or Sicily he could wrest from the Greek schismatics or the Saracens. With the aid of his younger brother Roger he conquered Sicily, and ejected the Saracens from their remaining possessions in southern Italy. The kingdom of Naples had its origin in these conquests.
Robert, having subsequently undertaken to annex the duchy of Benevento to his dominions, was brought into collision with Pope Gregory VII., who claimed the territory as a grant from the emperor of Germany. The pope excommunicated him, but a reconciliation was soon effected. In 1081, under the pretext of sustaining the rights of Constantine, son of the dethroned emperor Michael VII., who had married his daughter, he invaded Epirus and other provinces of the Byzantine empire, and after a series of victories was in full march for Constantinople, when he was recalled to Italy to relieve the pope, who was besieged by the emperor Henry IV. in the castle of Sant' Angelo. At Guiscard's approach Henry drew off his forces; but the populace having refused to receive the Normans, Rome was sacked by them, and a large portion of it burned. The pope, fearing to remain in the city, followed his liberator to Salerno, where he died soon after. Guiscard immediately sailed with a large fleet for the Grecian archipelago, but died of an epidemic disease at Cephalonia on the eve of his departure for Constantinople.