Robert I, Duke of Normandy the father of: Robert I, Duke of Normandy Robert the Magnificent (; 22 June 1000 – 1–3 July 1035), was the Duke of Normandy from 1027 until his death in 1035. Owing to uncertainty over the numbering of the Dukes of Normandy he is usually called Robert I, but sometimes Robert II with his ancestor Rollo as Robert I. He was the son of Richard II and brother of Richard III, who preceded him as the Duke. Less than a year after his father's death, Robert revolted against his brother's rule, but failed. He would later inherit Normandy after his
William of Jumièges "De moribus et actis primorum Normannorum ducum", between c. 996 and c. 1015. This work was commissioned by Duke Richard I, and "was renewed by his half-brother, Count Rodulf of Ivry, and his son Duke Richard II (996-1026)... Dudo's work was taken up by William of Jumièges in the 1050s, who revised, abbreviated and updated his "De moribus" and added an account of the reigns of Dukes Richard II, Richard III (1026-7), Robert I (1027-35), and William II [William the Conqueror]." He finished this by 1060 but added to it later when William the Conqueror had become king of England,