Ah, the trusty Bluetooth logo. It's just a pointy ‘B', right? Like most of the countless logos we set eyes on every single day, we've hardly stopped to ruminate on the design for everyone's   wireless technology standard. But two decades on from its deployment, the internet is just discovering the fascinating story behind Bluetooth's name and logo.

According to one of the engineers behind the development of Bluetooth, the name belongs to a Viking-era king with a bad tooth. And not only that, but like many of the best logos of all time, the icon is hiding a secret message.

Engineers Sven Mattisson Jim Kardach were working on the technology in the late 1990s when they realised it needed a catchy name to make it stand out from the confusing plethora of wireless tech being developed at the time. And the concept of ‘Bluetooth' was, like all the best ideas, devised over a beer.

According to France24(opens in new tab), the two men began discussing history while drowning their sorrows after a disappointing pitch. They “talked at length” about Vikings, including the king of Denmark, Harald “Bluetooth” Gormsson – a name said to refer to his dead tooth.

The king is most famous for uniting Norway and Denmark, a parallel which delighted Mattisson and Kardach who were “seeking to unite the PC and cellular industries with a short-range wireless link” (which is, of course, exactly the same as bringing warring nations together).

But it isn't just the name that has a surprising history – the Bluetooth logo is also hiding a secret. It turns out the design actually contains two letters, rather than just a slightly insect-like B. What you're actually looking at is a superimposition of the Nordic runes for the letters H and B (below), for ‘Harald Bluetooth'.