What is "hagrold"

Hagrold ( fl. 944–954), also known as Hagroldus, Harold, and Harald, was a powerful tenth-century Viking chieftain who ruled Bayeux. He was apparently a pagan from Scandinavia, and seems to have seized power in Normandy at about the time of the death of William, Count of Rouen. His career can be interpreted in the context of aiding the Normans against the intrusion of Frankish authority, or conversely in the context of taking advantage of the Normans.