A stone marker set up in the Polish town of Wolin commemorates the death of Danish King Harald Bluetooth on what may have been the site of the legendary Viking fortress, Jomsborg.

Most evidence of the existence of Jomsborg and its warriors, the Jomsvikings, comes from medieval legends and histories, and the legends and histories come from different cultures and call the fortress different things. Comparisons of the stories have led some scholars to place the fortress, which was probably a ring fortress after the style of the time, and which probably had a harbor that held anywhere from three to 360 ships, in or near the modern day town of Wolin.

The Jomsvikings were supposed to be a dangerous and elite fighting force of men between the ages of 18 and 50 who held to a strict code. Some say they were mercenaries, loyal only to their leader, some say they were Bluetooth’s men. They were very selective, requiring one to defeat, if not kill, a current Jomsviking in order to join. Women and children were not allowed in the fortress, nor were the warriors allowed to take them as prisoners in battle.

The stone marker, located in a park near the Dziwna Channel of the Oder River, refers in Polish and in Runes to Bluetooth’s death in Wolin in the year 986, which, according to legend, was the result of a fight just outside the gates of the fort. Bluetooth is also credited with having built the fort in the first place, in the 960s. If it ever existed, it was destroyed in 1043 by King Magnus the Good of Norway. Or maybe it was washed away by storm floods from an island northwest of Wolin, another location considered to be a possible site of Jomsborg. Little is certain.

Harald Bluetooth, who may have gotten his nickname from a bad tooth (he was also known as Gormsson, his father’s name having been Gorm), has another, more widely known modern day tribute. The symbol for Bluetooth technology is made up of the runes for H and B.