Robert was probably the eldest of Henry's many illegitimate children. He was born before his father's accession to the English throne, either during the reign of his grandfather William the Conqueror or his uncle William Rufus. (Wikipedia article). Through his father King Henry I of England and Duke of Normandy, Robert was made one of the richest and most powerful men in the Anglo-Norman world. Geoffrey of Monmouth dedicated his History of the Kings of England to Robert, and William of Malmesbury wrote the earl's first biography in Historia Novella. Most famous for his devotion to his sister Matilda Empress and her claim to the Anglo-Norman empire, Robert died before the Anarchy ended. His death almost spelled the end of Matilda's cause.