Norman adventurer conspicuous in the conquest of of southern Italy and Sicily.
Count of Apulia and Calabria 1057 to 1059
Duke of Apulia and Calabria from 1059
Prince of Benevento 1078 to 1081
His cavalry charge at the Battle of Dyrrhachim, October 18, 1081 turned the battle into the Byzantine centre and caused the bulk of the Byzantine army to rout.

Anna Comnema (1083 to 1153) a Byzantine Historian describes him
This Robert was Norman by birth, of obscure origins, with an overbearing character and a thoroughly villainous mind; he was a brave fighter, very cunning in his assaults on the wealth and power of great men; in achieving his aims absolutely inexorable, diverting criticism by incontrovertible argument. He was a man of immense stature, surpassing even the biggest men; he had a ruddy complexion, fair hair, broad shoulders, eyes that all but shot out sparks of fire. In a well-built man one looks for breadth here and slimness there; in him all was admirably well-proportioned and elegant... Homer remarked of Achilles that when he shouted his hearers had the impression of a multitude in uproar, but Robert’s bellow, so they say, put tens of thousands to flight.

First wife Robert. He repudiated her due to consanguinity

Second wife of Robert Guiscard
A Lombard princess
Also known as Sichelgaita or Sigelgaita
Frequently accompanied her husband on his conquests.