Where did the name of the stone come from? According to legend, it owes its name "Karlstein" to Charlemagne, King of the Franks. This is said to have laid to rest on the stone during the Saxon wars. Under threat of death, his followers were forbidden to wake him. While he slept, enemy Saxons approached. Since none of Charles' entourage wanted to be in danger, the ruler's dog was thrown on the sleeping man. He awoke and saw the impending danger and cried: "As surely as I will split this stone with my sword, so surely we will defeat the Saxons." Jumped on his horse, which jumped over the stone, and split the stone with one blow. He defeated the Saxons. Today, the horse's horseshoes and the dog's paws in the stone are meant to commemorate the event.
According to scientific research conducted in 1951, the stone is in its original geological location. Coming from southern Sweden, it was transported by the glacier masses of the Ice Age and remained where it is today after they melted around 10,000 years ago. The deep grooves on its back are natural, weathered drainage joints in the rock. The horseshoe marks in the stone are of human origin. Unfortunately, the meaning is not known.
There are stones with horseshoe symbols in various places in northern Germany. The next stone of this kind was in Regesbostel in the district of Harburg. Near Rosengartenstraße in the Rosengarten state forest, it used to serve as a boundary stone, place of execution or place of worship.