Harald Bluetooth: A Viking King That “Named” One Of The Most Used Technology Today

How did a modern wireless short-range communications technology standard come to be named after a Viking king Harald Bluetooth who lived over a thousand years ago?

Sometime in the AD 950’s on a warm and sunny day, a party of Danes anchored their boats and went swimming at a bay in Northumbria which is now Northern England and south-east Scotland. For years, the Danes had been raiding up and down the coast.

King Adelbrecht of Northumbria had responded to the Viking invasion of Prince Canute and Prince Harald Bluetooth by raising an enormous army of locals. After many bloody clashes where thousands of warriors fell, the two armies met near the town of Scarborough.

This time, the Danes were victorious and defeated King Adelbrecht’s army. The Vikings spent the next several months subduing small rebellions and imposing their authority on the locals.


On their way to York, a group of Viking warriors took a rare holiday to relax, trusting that they were safe and Norse rule has been accepted. However, they were completely wrong, resentment burned hot in the hearts of the locals. While the warriors were frolicking in the water, nearby villagers mounted a surprise archery attack from the beach and several Vikings were killed, including the leader, Prince Canute, favored eldest of King Gorm the Old.

Harald Bluetooth became the King of Denmark

Jelling – riget og regenten, by Ida Maria Schouw Andreasen, Benni Schouw Andreasen, Vejle Kommune on Flikr.com, licensed under CC BY-SA 2.0

Prince Harald Bluetooth, the younger son managed to survive the onslaught of arrows. Invigorated by Canute’s death, King Adelbrecht returned and rallied his subjects, ultimately forcing the Danes to leave the area and return to Denmark.

As a result, King Gorm’s younger son Harald “Bluetooth” Gormsson became the heir apparent and ascended to the throne after his father’s death. Actually, modern historians are not exactly certain how Canute died; the blitz at the beach is one of the more commonly told legends memorialized in the Olav Tryggvason saga, a heroic series of tales detailing the exploits of Óláfr Tryggvason, a 10th-century Norwegian king.


Anyway, it’s the death of Harald’s older brother that paves the way for Harald Bluetooth to become king. Perhaps witnessing his brother’s death affected how he viewed the world and why he sometimes tried diplomacy before military might and converted to Christianity, making him an influential figure of modern Denmark.

Harald was born around 920 to King Gorm and Thyra Dannebod, a noblewoman. King Gorm who ruled approximately 22 years from 936 to his death around 958 strongly exerted his authority over nearby provinces and set up a new seat of power in Jelling, northern Jutland.

Gorm began to unify Denmark into a single kingdom and Harald continued this work. Harald was also known as ‘Harald Bluetooth’ or simply ‘Bluetooth’, an old Norse term for ‘dark colored’ for possibly having a prominent discolored tooth. He became king around 958 and ruled for about 28 years until 986.


His goal was to continue his father’s goal – to unify Denmark

Jelling – riget og regenten, by Ida Maria Schouw Andreasen, Benni Schouw Andreasen, Vejle Kommune on Flikr.com, licensed under CC BY-SA 2.0

When Harald Bluetooth took to the throne, Denmark was a land split into multiple “clans” and territories, each owing allegiance to local rulers. While Gorm had united most of Jutland, the outer coastal regions and islands were still under their own rule.

Harald Bluetooth was an ambitious ruler who immediately set about subjugating the smaller clans and islands through both diplomatic and military campaigns to form a unified Denmark. At the same time, Harald fought off the Germans under Otto I who threatened Denmark from the south.

Harald’s sister, Gunnhild was married to King Erik Bloodaxe of Norway. She fled to Harald Bluetooth with her five sons when her husband was killed in a battle for the throne with his half-brother King Hakon in 954. Harald strategically supported his nephews and helped them reclaim territories in Norway from King Hakon around 961.


Unfortunately, his nephews were authoritarian, heavy-handed rulers causing resentment and unrest in the country. Within a few years, King Harald Greycloak, the eldest nephew ended up being assassinated and Harald Bluetooth came to rule Norway.

Harald converted his faith to Christianity

Jelling – riget og regenten, by Ida Maria Schouw Andreasen, Benni Schouw Andreasen, Vejle Kommune on Flikr.com, licensed under CC BY-SA 2.0

Sometime in the early 960’s Harald Bluetooth converted to Christianity. He may have been exposed to this foreign religion as a child through Thyra his mother. Legend has it that a skeptical Harald became convinced that Christ was the strongest god when a cleric named Poppo performed a miracle by carrying a red-hot massive iron weight in his hands without getting burned.

Others claim Otto 1 defeated Harald Bluetooth in battle and forcibly converted him by the edge of a sword. However, most likely Harald’s conversion to Christianity was a skillful political decision; if he was now a Christian and encouraging his subjects to also turn from their pagan ways and convert, it made it hard for the Germans to meddle in Danish affairs.


At great cost, Harald Bluetooth undertook several public works and defense projects. Some of these projects may have been a shrewd and calculating way for Harald to gain influence with locals he brought under his rule. The projects also allowed him to consolidate economic and military control of the kingdom.

Harald unified Denmark

Jelling – riget og regenten, by Ida Maria Schouw Andreasen, Benni Schouw Andreasen, Vejle Kommune on Flikr.com, licensed under CC BY-SA 2.0

Harald Bluetooth built a massive burial mound for his father, which mirrored the mound his father had constructed for Thyra upon her death. Around the 960’s to thwart the Germans tribes attacking from the south, Harald expanded and strengthened the “Dannevirke”, a defensive earthwork and wood “wall” around the main trading town of Hedeby along the southern border of his kingdom. He also safeguarded the harbor with a boundary of stakes.

Around 965, Harald Bluetooth ordered the creation of a Jelling stone, the first stone being erected by his father. The runic inscriptions on the monument honor Harald’s parents and celebrate his conquest of Denmark and Norway, and his conversion of the Danes to Christianity.


Not only was this runestone a public symbol of the unification of Denmark, and it was a cunning proclamation to everyone, especially to German King Otto I who had by now been crowned Holy Roman emperor, and the archbishop of Hamburg-Bremen that the Danes were Christians. He also moved his parents from their pagan resting mounds and reburied them under a Christian church he built.

He built fortresses all around

Trelleborg ring fortress today in Slagelse, by Thue C. Leibrandt, licensed under CC BY-SA 3.0 via Wikimedia Commons

In 979 he fortified the fortress of Aros which was situated in a central position in his kingdom. Soon after that, he had Trelleborg ring fortresses built in five strategic locations on conquered land with Aarhus perfectly in the middle.

The forts were used for military purposes, but it has also been suggested that the forts may have served as administrative centers as well as royal lodging for when Harald traveled around Denmark.


Harald Bluetooth also constructed a defensive dyke in the south called Kovirke in the 980s. Medieval historians credit Harald with founding the town of Roskilde also around this time and building an elaborate church there.

Throughout his rule, Harald Bluetooth continued his various military campaigns and over a decade retained considerable clout. When Otto’s successor and son Otto II was busy fighting in Italy, Harald took advantage of the distraction by sending his son, Sweyn Forkbeard to raid Otto’s fortress in Slesvig.

In 974, Harald’s army lost to the Germans at the Danevirke, and Germans began moving back into the border area between Scandinavia and Germany. They were driven out of Denmark again in 983 by an alliance of troops loyal to Harald Bluetooth. However, over time Harald’s hold on the borderlands and also Norway became tenuous.


Harald’s son became hungry for power

Jelling – riget og regenten, by Ida Maria Schouw Andreasen, Benni Schouw Andreasen, Vejle Kommune on Flikr.com, licensed under CC BY-SA 2.0

To make matters worse, Sweyn was power hungry and followed the Norse pagan religion, not Christianity, and began clashing with his father over military plans. Around 986, Sweyn Forkbeard denounced his father, condemning him to death and started a rebellion to fight him for the kingdom of Denmark.

There are many conflicting tales of how Harald Bluetooth exactly died, the Saga of Olaf Tryggvason says that he was struck down in a battle that took place at Ise fjord. Another saga says that Harald Bluetooth fell at Bornholm and yet a third saga says that it was near Mols. Ultimately, Harald suffered a violent, bloody death and was allegedly buried under a church in either Roskilde or Jomsborg.

While some medieval historians saw Harald Bluetooth in a negative light, thinking him brutal, greedy and sly, for modern Denmark he’s considered a more heroic and nuanced figure. Through military might and skillful negotiations, he unified Denmark and also brought Christianity and a distinct Danish identity to his people.


The technology named after Harald Bluetooth

BlueTooth Logo that contains the two letters, by House, Public domain, via Wikimedia Commons

In the late 1990’s Intel, Ericsson, and Nokia held several meetings to figure out standards for short-range radio technology to support connectivity and collaboration between different devices and industries.

An Intel mobile computing engineer named Jim Kardach was reading a book about Vikings and suggested that ‘Bluetooth’ be used as a code name. To quote Jim ‘King Harald was famous for uniting Scandinavia just as we intended to unite the PC and cellular industries with a short-range wireless link.’

Later, the companies wanted to use either RadioWire or PAN (Personal Area Networking) as the technology’s official name. However, the media had latched on to the code name, and it had already spread throughout the internet. So Bluetooth stuck and the symbol for Bluetooth technology is made up of a Younger futhark bindrune for King’s initials, H [ᚼ] and B [ᛒ].


Featured image: Jelling – riget og regenten, by Ida Maria Schouw Andreasen, Benni Schouw Andreasen, Vejle Kommune on Flikr.com, licensed under CC BY-SA 2.0

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