Which Viking king gave his name to Bluetooth wireless technology?

Harald Bluetooth gave his name to Bluetooth wireless technology.

Harald Bluetooth was a 10th-century Danish king who also ruled Norway for part of his reign. He is remembered for consolidating Denmark and promoting Christianity in the region. The large Jelling Stone, raised by Harald, presents him as the ruler who united Denmark and made the Danes Christian.

Bluetooth technology adopted Harald’s name in the 1990s because its developers saw him as a symbol of uniting different groups. The logo combines two runes from the Younger Futhark alphabet: Hagall, or H, and Bjarkan, or B, representing Harald’s initials.

Harald’s nickname probably referred to a distinctive dark or dead tooth, although the exact origin is not certain. He should not be confused with Harald Fairhair, traditionally described as the first king to unite Norway, or with his son Sweyn Forkbeard, who later conquered England.