Robert did not claim the crown on his brother's death in 898, but recognized the Carolingian king, Charles III; Robert continued to defend northern France from Norman attacks as "duke of the Franks"; about 921 he gathered support for his claim, and drove Charles into Lorraine; 06-29-922 he was crowned at Rheims and the next year faced Charles' attempt to oust him, during which "in a stubborn and sanguinary battle near Soissons, Robert was killed, according to one tradition, in single combat with his rival." {-Encyclopaedia Britannica, 1956 Ed., 19:346}

References: [AR7],[Weis1]