Today I found out the Bluetooth standard is named after a 10th century Scandinavian king.

The man was Harald I of Denmark.  “Bluetooth” is the English translation of “Blåtand”, which was an epithet of Harald I (Harald Blåtand Gormsson).  Legend has it, he received this name due to being extremely fond of blueberries and consuming them so regularly and in such volume that they stained his teeth blue.

The Bluetooth standard was originally developed by Jaap Haartsen and Sven Mattisson in 1994, working at Ericcson in Sweden.  Because Bluetooth was meant to offer a set unified standard, replacing a variety of competing protocols, particularly the somewhat antiquated RS-232, they decided to name it after the 10th century king, Harald Blåtand Gormsson, who completed his father’s work of unifying the various Danish tribes into one Danish kingdom around 970. Although, he was only able to maintain this unification for a few years.

The name Bluetooth wasn’t originally necessarily meant to be the final name of the standard.  When they first named it thus, it was just a code name for the technology.  It ultimately ended up sticking though and became the official name of the standard.

The Bluetooth logo also derives from “Harald Blåtand”, with the long-branch Nordic runes for “H” and “B” comprising the design you see in the blue oval of the logo.

Bonus Facts:

• Although the wireless Bluetooth standard was developed to be ultra low power and short range, with proper directional antennas and focusing, researches have been able to achieve a range of a little over one mile with a standard Class 2 Bluetooth device which is supposed to only have a maximum range of around 30 feet.
• Nearly 95% of all mobile phones have Bluetooth capabilities.
• Because Bluetooth devices are now so prevalent and the standard itself has some security flaws, they have relatively recently become targets of attacks, such as the 2005 Lasco.A worm, which targeted mobile phones using the Symbian OS.  Any of those devices with their Bluetooth enabled could replicate themselves to other Bluetooth enabled devices of the same type within range.
• Also in 2005, thieves looking for expensive devices in cars would use their own Bluetooth enabled device to locate other Bluetooth enabled devices left in the cars.  Once located, the thieves would then break into the cars and steal the devices.
• Since 1998, the Bluetooth standard has been managed by Bluetooth SIG (Special Interest Group) which is currently comprised of over 14,000 telecommunication companies across the globe, such as Ericsson, IBM, Toshiba, Intel, Nokia, etc.
• Harald I of Denmark was the offspring of King Gorm the Old and Thyra Dannebod.  The famed Jelling stones at Jelling church in Denmark were erected in honor of King Gorm and Thyra. The runes read:  “King Harold bade these memorials to be made after Gorm, his father, and Thyra, his mother. The Harold who won the whole of Denmark and Norway and turned the Danes to Christianity.”  These stones are particularly famous in Denmark due to being a symbol of when Denmark first became a nation state.
• Harald I was able to maintain control of Norway for only a short time before losing to the Germans near Danevirke in 974, which subsequently saw him lose control of many of the tribes under his rule and saw the Germans re-take much of the land bordering Scandinavia and Germany.
• Harald I and certain West Slavic tribes were able to drive out the Germans in 983.  However, shortly thereafter, Harald I’s son, Swein, is thought to have led a rebellion against is father, which ultimately lead to the death of Harald I around 985-986.