sentences:  Robert founded the importance of his fief by marrying Gaitelgrima, daughter of Guaimar IV of Salerno and Drogo of Hauteville, the two most powerful south Italian lords of the day.Robert was succeeded by his sons, Richard, Henry, and William, in succession.Henry renounced the suzerainty of the Duke of Apulia, Roger Borsa, and began to chart an independent course, giving his allegiance to the Byzantine Empire and dating his charters by the reign of Alexius I Comnenus.