Saw a thing on tv about ancient Scandinavian history, and then you’ll always hear about Harald Blåtand.
Harald Blåtand (Bluetooth) was a Danish king that lived between c. 935 and c. 985 or 986, ruled Denmark and larger parts of Scandinavia from around 958.
So why naming a radio communication protocol after an old Danish king?
Since he was apparently very good at getting various people talking, getting different tribes to get along. And so on.
The bluetooth logo is his initials written in runes (H and B) combined, the B is a bit stylized to look better I guess.