Harald Bluetooth (Harald “Blåtand” Gormsson) was the King of Denmark between 958 and 970 AD. According to some scholars, Harald got the nickname ‘Blåtand’ (‘Bluetooth’) because of his bluish or black tooth. However, this tooth never hindered him from becoming a great uniter: the King managed to unify parts of Denmark and Norway into one nation and convert the Danes to Christianity.
Moreover, his name came to be used in the field of wireless communication, which lacked unity in the mid-1990s. Numerous corporations were then developing competing, incompatible standards, this being generally considered as an impediment to the widespread adoption of wireless.
Jim Kardach, one of the founders of Bluetooth SIG, decided to do his utmost to bring various companies together and “develop an industry-wide standard for low-power, short-range radio connectivity” (PC World 2013).
It so happened that at that time Kardach was reading a book about King Harald, whom he viewed as an ideal symbol of unification. “Bluetooth was borrowed from the 10th-century, second king of Denmark, King Harald Bluetooth; who was famous for uniting Scandinavia just as we intended to unite the PC and cellular industries with a short-range wireless link,” he explained later.
In fact, the Bluetooth logo—a cryptic symbol in a blue oval—actually stands for the initials of Harald Bluetooth written in Scandinavian runes.