Harold I of Denmark

Harald Bluetooth
Harald being baptized by Poppo the monk, in a relief dated to c. 1200.
King of Denmark
Reign	c. 958 – c. 986
Predecessor	Gorm the Old
Successor	Sweyn Forkbeard
King of Norway
Reign	c. 970 – c. 975/986
Predecessor	Harald Greycloak
Successor	Sweyn Forkbeard
Regent	Haakon Sigurdsson (de facto ruler)
Died	986/87
Spouse	Gyrid Olafsdottir (m) Tove (m)
House	House of Gorm
Father	Gorm the Old
Mother	Thyra
Religion	Christianity (Pre-Schism)

Harald "Blåtand" Gormsson (Old Norse: Haraldr blátǫnn Gormsson, Danish: Harald Blåtand Gormsen) (probably born c. 935) was a king of Denmark and Norway.

He was the son of King Gorm the Old and of Thyra Dannebod. He died in 985 or 986 having ruled as King of Denmark from c. 958 and King of Norway for a few years, probably around 970. Some sources say his son Sweyn Forkbeard forcibly deposed him.

Harald had the Jelling stones erected to honour his parents. The Encyclopædia Britannica considers the runic inscriptions as the best-known in Denmark. The biography of Harald Bluetooth is summed up by this runic inscription from the Jelling stones:

"King Harald bade these memorials to be made after Gorm, his father, and Thyra, his mother. The Harald who won the whole of Denmark and Norway and turned the Danes to Christianity."

King Harald Bluetooth's conversion to Christianity is a contested bit of history, not least because medieval writers such as Widukind of Corvey and Adam of Bremen give conflicting accounts of how it came about.

Widukind of Corvey, writing during the lives of King Harald and Otto I, claims that Harald was converted by a "cleric by the name of Poppa" who, when asked by Harald to prove his faith in Christ, carried a "great weight" of iron heated by a fire without being burned.

Adam of Bremen, writing 100 years after King Harald's death in "History of the Archbishops of Hamburg-Bremen", finished in 1076, describes Harald being forcibly converted by Otto I, after a defeat in battle. However, Widukind does not mention such an event in his contemporary Res gestae saxonicae sive annalium libri tres or Deeds of the Saxons. Some two hundred and fifty years later, the Heimskringla relates that Harald was converted with Earl Haakon, by Otto II.