In 1081 the Normans under Robert Guiscard possessed themselves of Durazzo; Guiscard's son Bohemund defeated the Greeks in several battles and again (i 107) laid siege to Durazzo, which had been surrendered to them by treachery; failing to take the city, he retired to Italy in 1109.
He maintained an alliance with the Norman Duke Roger, Robert Guiscard's son and successor, and united the German with the Italian opposition to the emperor by promoting the marriage of the Countess Matilda with young Welf of Bavaria.
In March 1711, by Guiscard's attempt on his life, Harley got the wound which had been intended for St John, with all the credit.
Roger's rule in Sicily was more real than Robert Guiscard's in Italy.
He served under his father in the great attack on the East Roman empire (1080-1085), and commanded the Normans during Guiscard's absence (1082-1084), penetrating into Thessaly as far as Larissa, but being repulsed by Alexius Comneus.
The Norman danger ended for the time with Robert Guiscard's death (1085) and the conquests were recovered.
The second crusade (1147-48) gave Roger an opportunity to revive Robert Guiscard's designs on the Greek Empire.
With little or none of Robert Guiscard's personal valour, and living at intervals the life of an eastern Sultan, he yet showed to the full his uncle's audacity, diplomatic skill and determination.