is used worldwide, connecting devices from to with ease. There are few people who haven't heard of Bluetooth or used it in their daily lives. However, the origins of its name and logo remain a mystery to many, with a dating back over 1,000 years.

The name Bluetooth comes from , a Viking king who ruled and in the 10th century. He was known for uniting the and bringing to Denmark. In 1997, engineers developing a wireless communication standard chose the name as a reference to his ability to connect people, just as Bluetooth technology connects devices.

The distinctive Bluetooth logo also has ties to the Viking ruler. It is a combination of two runes from the Younger Futhark alphabet: (H) and (B), which are the initials of Harald Bluetooth's name.

These runes were used in Old Norse inscriptions and appear on historic relics such as the Jelling stones, a set of carved runestones in Denmark that were erected by Harald himself.

Harald's rule was marked by military expansion and infrastructure development.

He fortified Denmark with a series of circular ring forts, some of which still exist today, and built what is believed to be the oldest known bridge in southern Scandinavia, the Ravning Bridge. He also introduced the first nationwide coinage in Denmark.

The reason behind his nickname, "Bluetooth," is uncertain. Some historians believe he had a dead tooth that appeared dark blue or black, while others suggest it could be a reference to his reputation as a "dark thane" in England.

Regardless of its origin, his name has now been immortalised in modern technology.

Nonetheless, Harald's reign eventually ended in conflict. After losing a battle against the Holy Roman Empire, he was later overthrown by his own son, Sweyn Forkbeard, and is believed to have died in 986.

His burial site remains debated, but some evidence suggests he may have been laid to rest in the church at Jomsborg, a Viking stronghold in what is now Poland.

The decision to name Bluetooth technology after the Viking king was initially meant to be temporary.

Engineers working on the project used "Bluetooth" as a code name, but it ended up becoming the official branding when no better alternative was agreed upon.