In 1999, the Swedish electronics company Ericsson developed a technical standard (a document containing specific technical specifications) capable of transmitting various types of data (photos, audio, video) between different devices (phones, PCs, etc.) using short-range radio frequencies without wires. This technology, which we all know as Bluetooth, became widely used in the early 2000s and is now especially popular for connecting devices like speakers and headphones. Its symbol consists of the Nordic runes B and H (Berkanan and Hagalaz), representing hospitality and change. 

But what led Ericsson to name this invention "Bluetooth"? The origin of the nickname is tied to the historical figure of Harald (or Harold) I Gormsson, King of Denmark and Norway (911–987). This Viking king was known as "Bluetooth" (Blåtand in Old Norse) because he allegedly painted his teeth blue to intimidate enemies during battles. 

The son of King Gorm "the Old" and Thyra, Harald was raised by his father in the ways of kingship and warfare, while his mother instilled in him a strong devotion to Christianity. At that time, the Kingdom of Denmark (like neighboring Norway) was fragmented into small kingdoms, comprising only the current Jutland Peninsula. After his father’s death, Harald assumed power in 958, inheriting a divided and challenging territory to govern. 

Starting in 960, Harald initiated an expansionist policy that strengthened the Danevirke (a series of wooden walls at the border with Germanic kingdoms) and led to the conquest of Norway and Northumbria. At home, he accelerated the conversion of the Danes to Christianity, a strategy that also helped him achieve greater political unity. This is reflected in a runestone inscription he left behind: "King Harald ordered these monuments made in honor of Gorm, his father, and Thyra, his mother. Harald who won all of Denmark and Norway and made the Danes Christians." 

Just as Harald Blåtand united different Danish tribes, Bluetooth technology is inspired by the king, connecting various devices for seamless communication.