
Born in 1028, William was the elder of two illegitimate sons born to Arlette of Falaise and Duke Robert I of Normandy (d. 1035). He grew up in a murderous atmosphere, protected by his determined mother, but by the age of 15 was strong enough to begin his own rule. William soon proved a vigorous soldier, defeating rebels to enforce his rule on Normandy; his methods were simple, often brutal, always effective.