Weis' "Ancestral Roots . . ." (162:16). "Europaeische Stammtafeln", Band II, Tafeln 5-6.
The first ruler of Flanders of whom history has left any record is Baldwin, surnamed Bras-de-fer (Iron Arm) This man, a brave and daring warrior under Charles the Bald, fell in love with the king's daughter Judith, the youthful widow of two English kings, married her and fled with his bride to Lorraine. Charles, though at first very angry, was at last conciliated and made his son-in-law Margrave (Marchio Flandriae) of Flanders [in 862], which he held as an hereditary fief. The Northmen were at this time continually devastating the coast lands and Baldwin was entrusted with the possession of this outlying borderland of the west Frankish dominion in order to defend it against the invaders. He was the first of a line of strong rulers, who at some date early in the 10th century exchanged the title of margrave for that of count.

North of the Seine, Baldwin of Flanders received responsibility for defending this highly exposed region against the Northmen. As Jan Dhondt has shown, his family stemmed from the middle Rhine and Alsace, while the count himself had received duties in Flanders and settled there. In 862 Baldwin, later nicknamed Ironarm, eloped with Judith, the daughter of Charles the Bald, with the help of Louis the Stammerer. After taking refuge in the realm of Lothar II, the pair sought help from Pope Nicholas I to obtain the pardon of the West Frankish king. After his fury subsided, Charles received the couple back, and bestowed on Baldwin a series of counties as well as the abbey of St. Bertin. Baldwin proved himself worthy of this great trust. He repulsed every attack mounted by the Northmen until his death in 879.121

In the north of western Francia proper, Flanders was exposed to Viking attack. The death of Baldwin I in 879 came at a time of renewed aggression.121