Pick up almost any connected product — a fitness band, a smart lock, a set of wireless earbuds, an industrial sensor reporting to a phone — and somewhere inside it is a radio that traces its name to a 10th-century Danish king. Bluetooth, the short-range wireless standard now embedded in billions of devices, is named after Harald "Bluetooth" Gormsson, and the reason it carries that name is worth more than a piece of pub trivia. It's a small lesson in what makes connected hardware actually work.
The king, the codename, and the rune
Harald Gormsson ruled Denmark in the late 900s and is remembered for uniting the warring Danish tribes — and, for a time, Norway — under a single crown. His nickname, Blåtand in Old Norse, is usually translated as "Bluetooth," likely a reference to a dead or discoloured tooth.
The leap from Viking history to wireless radio happened in 1997. Jim Kardach, an engineer at Intel, was part of an industry effort to get the PC and mobile-phone worlds to agree on a single short-range radio link. At the time the project needed a placeholder name. Kardach had been reading about Scandinavian history, and the parallel struck him: just as Harald had united fractious kingdoms, this new standard would unite the computer and cellular industries that otherwise spoke incompatible languages. "Bluetooth" went in as a temporary codename.
