Here’s a fun fact: the technology known as Bluetooth was named after a Viking king named Harald Bluetooth. King Harald’s real last name was Gormsson for he was King Gorm’s son and a lot of Viking last names were like that. It was also pretty common for Vikings to give their rulers interesting nicknames that described something about that person. For example, there was Ragnar Shaggy-Breeches, Bjorn Ironside, Ivar the Boneless, and Sigurd Snake-in-the-Eye. In Harald’s case, one of his front teeth was rotten and looked blue—hence, Bluetooth.

King Harald was a pivotal character in Scandinavian and Viking history. He ruled at the tail end of the Viking age, from about 958CE–986CE. The Viking age lasted for about 300 years, from around 800CE—1050CE. It was a time when Vikings were at their peak in terms of terrorizing Europe. This was the time when they invaded many areas of Europe, killing, robbing, killing, burning villages, destroying churches, killing more people, and taking Europeans as slaves. They were fierce warriors and famously merciless.

Interestingly, the Vikings weren’t a unified people, nor were they very good at working together. They were mostly made up of lots of different tribes who fought each other at least as often as they fought other Europeans. Most Vikings lived in a region called Scandinavia. Today, the term Scandinavia generally refers to three countries: Denmark, Norway, and Sweden.

Harald was the first Viking king to bring both Christianity and unity to the Viking people. And it seems that Christianity and tribal unity brought an end to the Viking Age. Therefore, you might say that King Harald Bluetooth ushered in the end of the Viking Age. Before 1050CE, most Vikings were pagans who worshiped gods like Odin and Thor. King Harald was one of the first well-respected Viking kings to convert to Christianity. He encouraged the people he ruled over to convert to Christianity as well. Then he started to unite the other Viking tribes in Denmark. He became known as the king that united Denmark. Then, so the rest of the world would remember how great he was, he erected a monument to himself in Jelling (YELL-ing), Denmark known as the Jelling Stones. The stones feature Viking runes (a type of writing that uses symbols) that describe the great deeds of the fantastic King Harald.

Fast-forward about one thousand years to the mid-1990s. Wireless communications are becoming popular. Cellphones have moved from being brick sized to, well, being less than brick sized. Technology companies are working on a short-range, wireless device that can connect computers with cellphones and other equipment. Unfortunately, each company is inventing its own system. It is very unusual for technology companies to work together. But the tech companies realize that if they work together, they can create one device that is compatible with all computers and cellphones.

Intel is one of the companies helping to develop the new device. Jim Kardach is one of the Intel engineers working on the project. He had recently learned about the story of King Harald Bluetooth. He thinks “Bluetooth” will be a great code-name for the project because the technology they are developing is uniting the tech companies in the way that King Bluetooth united Denmark.

Soon all the companies are calling it the “Bluetooth” project. It is easier to say than some of the other names they’d tried, like  Biz-RF or MC-Link. The official name of the device is Personal Area Networking (PAN). And that’s the name the tech companies are officially calling it. But just before launching the product, the tech companies pan the name PAN. Instead, they go with Bluetooth, which sounds way cooler.

The familiar Bluetooth logo is made up of Harald Bluetooth’s initials. They used the ancient runes for H and B. When you combine the two runes, they become the Bluetooth logo. It’s kind of a beautiful story of unity, really. King Harald Bluetooth united Denmark. Developing the Bluetooth technology united the tech companies. And Bluetooth technology unites our cellphones with our computers and many other devices.