Bluetooth is named after a Viking king 

We see the name and iconic Bluetooth logo on virtually every device we own - headphones, speakers, even toothbrushes.

As it turns out, Bluetooth is named after a 10th-century Scandinavian king. Harald "Blatand" Gormsson was a Viking king who ruled Denmark and Norway from the year 958 until 985.

There are many accomplishments credited to him, but greatest of all is that he united Denmark and Norway under his rule. Gormsson was also known for his dead tooth, which had a very dark blue-grey shade. It was so prominent that his nickname was Blatand, which literally translates from Danish to "Bluetooth".

Fast forward to 1996, when the tech was being discussed, an Intel representative Jim Kardash suggested the name and his reasoning was that like the king who united Scandinavia, Bluetooth intended to unite the PC and cellular industries.