When King Haakon the Good of Norway met Harald Greycloak on the field of battle in 961, Haakon was outnumbered six to one. He fought hard, and bravely, but it wasn’t enough. The battle turned, and Haakon was killed—not just by an arrow, but by Gunnhild’s dark magic, if you want to believe the legends.
The real force behind the throne of King Harald Greycloak was Queen Gunnhild, Mother of Kings, who ruled Norway as a tyrant for nine dark years. Land and wealth were seized from disloyal jarls, military raids were launched against would-be usurpers, and all who opposed her were wiped out with extreme brutality.
As you can imagine, this sort of thing doesn’t last forever, and Gunnhild, Mother of Kings, was deposed yet again in 970, when another guy named Haakon got mad and raised an army to fight Gunnhild after she set his dad on fire. Supported by the oppressed nobles of Norway, Haakon took his forces into battle with Harald Greycloak, defeated him, and killed the king, and Gunnhild was forced to flee to the Orkneys once again.
Gunnhild went back to work trying to reclaim her throne, but another invasion by her other sons in 971 was defeated by Jarl Haakon. Haakon, not interested in keeping Gunnhild around to thwart him at every turn, made a deal with Harald Bluetooth of Denmark, and Harald sold out his own sister to secure a sweet treaty with Haakon. When Gunnhild returned to Denmark in 974, Harald had his now elderly sister arrested, and sentenced her to death by drowning in a bog.