Bryan McAllister’s personal reference notebook
July 30, 2026Short & citedBlog
Civic Viewpoint.
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Kept by Bryan McAllister — short guides, clear facts, and the Canadian angle when it matters.
People File • Historical

Harald Bluetooth

Harald Bluetooth, also known as Harald Blåtand Gormsson, was a 10th-century king of Denmark and, for a period, Norway.

Updated July 30, 20261 min readCited sources

Harald Bluetooth was a 10th-century king of Denmark and Norway. He is best known for consolidating Danish rule and introducing Christianity, and his name lives on in Bluetooth wireless technology.

Who was Harald Bluetooth?

Harald Bluetooth was a Danish ruler of the Jelling dynasty, son of King Gorm the Old and Thyra Dannebod. He became king of Denmark around 958 and later ruled Norway for a period. His nickname 'Bluetooth' may refer to a prominent tooth or a dark complexion.

What did he achieve?

Harald is credited with consolidating Danish territory, especially Jutland and Zealand, and extending his influence into Norway. He also introduced Christianity to Denmark, a major shift from Norse paganism. His reign marked a period of unification and religious change.

Why does his name matter today?

In 1997, the Bluetooth wireless technology was named after Harald Bluetooth. The name was chosen as an analogy for uniting separate devices, much as Harald was said to unite peoples and territories. The Bluetooth logo even combines the runes for his initials.

In short

  • Harald Bluetooth was a 10th-century king of Denmark and Norway.
  • He consolidated Danish territory and extended influence into Norway.
  • He introduced Christianity to Denmark.
  • Bluetooth technology was named after him for uniting devices.
Canadian angle

Bluetooth technology is widely used in Canada, so Harald Bluetooth’s name is familiar to Canadian readers through everyday wireless devices.

Quick questions

Who was Harald Bluetooth?
Harald Bluetooth was a 10th-century king of Denmark and, for a time, Norway. He was a member of the Jelling dynasty and the son of Gorm the Old and Thyra Dannebod.
What is Harald Bluetooth known for?
He is known for consolidating Danish rule, extending his power into Norway, and introducing Christianity to Denmark.
Why is Bluetooth named after Harald?
Bluetooth was named after him in 1997 because the technology was intended to unite devices the way Harald was associated with uniting peoples and territories.

Sources

  1. Wikipedia — https://en.wikipedia.org/wiki/Harald_Bluetooth
    Supports: Birth/death estimate, reign dates, parentage, rule in Denmark and Norway, and association with Bluetooth naming
  2. Encyclopaedia Britannica — https://www.britannica.com/biography/Harald-I-king-of-Denmark
    Supports: Harald I as king of Denmark, approximate life dates, and credit for early unification
  3. Bluetooth SIG — https://www.bluetooth.com/about-us/bluetooth-origin/
    Supports: Naming origin of Bluetooth and the analogy to uniting devices
  4. TheCollector — https://www.thecollector.com/harald-bluetooth-viking-technology/
    Supports: Overview of Harald's reign, Christianization, and later cultural legacy