Gilbert (also Giselbert or Gislebert), Count of Reims & Roucy, was the son of Renaud, Count of Reims and Alberade of Lorraine, daughter of Gilbert, Duke of Lorraine.
Later, Eudes I, Count of Blois, and the successor to Herbert le Vieux, entrusted Giselbert with the Viscouncy of Reims.
In 987, upon the death of King Louis V, Giselbert rallied without difficulty to his successor Hugh Capet, but nevertheless agreed to take an oath of allegiance in 990 to Charles of Lorraine, when the latter pressed his claims to the throne.
It was long thought Ebles I was the son of Giselbert and, to explain the appearance of the Ebles name in the house of Roucy, a daughter of the Duke of Aquitaine, William III "Towhead", from the house of Poitiers.
According to this hypothesis,[2] and knowing the names of the brothers and sister of Ebles I, Giselbert and this princess of Aquitaine would be the parents of: However, a recent study by Jean-Noël Mathieu,[5] based on onomastic data (the first names of Eudes and Lietaud are unexplained by the conventional theory) and patrimony (the lands of Rumigny and Marle, previously owned by the Counts of Blois) proposed a new explanation: that Ebles I of Roucy was the son of Ebles I of Poitiers, (himself the son of William IV of Poitiers and Emma de Blois) and a daughter of Aubry II, Count of Macon, and Ermentrude of Roucy, Giselbert of Roucy's sister.