Blåtand

This cool little app lets you control a variety of applications - iTunes, PowerPoint, etc. - from a Bluetooth-equipped Ericsson phone. It's even got a proximity sensor - when your Mac loses the signal from your phone, due to you walking out of the room, it can perform an action such as pausing the currently playing music track. Very cool.

Bluetooth, a wireless transmission standard which can be thought of a as a replacement for cables, was named after the 10th-century viking Harald Gormsson Blåtand. He conquered Denmark and Norway, sending his adopted son Harald Gråfäll to rule the latter kingdom in his stead. But, as often happens, once Gråfäll got his mitts on the tax revenue from Norway, he balked at sending tribute back to Blåtand. In retaliation, Blåtand sent his nephew Gull-Harald Knutsson to kill Gråfäll. No sooner had the assasination taken place then Knutsson himself was killed by Håkon Sigurdsson, sent by Blåtand to eliminate any connection between him and the murder of his foster son Gråfäll. Sigurdsson was given an earldom of most of northern Norway for his services. These guys were the original Sopranos.

Blåtand himself was baptised in 960, and is credited with having build the first cathedral in Scandinavia at Roskilde, Denmark. His attempts to conquer Sweden through his emmisary Styrbjörn Starke were crushed by Erik Segersäll, the king there.

I've read two explanations for the name "Blåtand," or Bluetooth. One holds that it was poor dental hygene which was responsible for the nickname, the other that Blåtand was a common name for somebody who had dark hair and/or skin. Have to do some more research on that one.