Harald Bluetooth

Harald "Bluetooth" Gormsson (Old Norse: Haraldr Blátǫnn Gormsson; Danish: Harald Blåtand Gormsen, died c. 985/86) was a king of Denmark and Norway.

The son of King Gorm the Old and Thyra Dannebod, Harald ruled as king of Denmark from c. 958 – c. 986, introduced Christianity to Denmark and consolidated his rule over most of Jutland and Zealand. Harald's rule as king of Norway following the assassination of King Harald Greycloak of Norway was more tenuous, most likely lasting for no more than a few years in the 970s. His son Swein Forkbeard forcibly deposed him from his Danish throne shortly before his death.

Source: Wikipedia — https://en.wikipedia.org/wiki/Harald_Bluetooth