Robert Curthose (c. 1050-1134): Oldest son of William the Bastard, Duke of Normandy, the future William the Conqueror of England. When William died, Robert became Duke of Normandy, but the title King of England went to his younger brother William II Rufus -- an outcome which naturally led to conflict between the brothers! Robert then went on the First Crusade, where he played a brave but not especially distinguished part. He was on his way home when William II was killed without leaving a son. Robert then hoped to become King of England, but Henry I grabbed the throne. In 1106, Henry conquered Normandy from Robert. Robert spent the rest of his life in Henry's custody.