Harold II "Blaatand" (Bluetooth), King of Denmark, King of Norway founded the Jomsborg Viking colony and established Christianity in Denmark. He was surnamed "the Old" because of the length of his reign--58 years. He was the first Christian king of Denmark, 931-979.
Swengen ruled as King of Denmark from 991 until his death at Gainsborough, England in 1014, when he was on one of his annual raiding expeditions to that county.