The spirit ship is a common theme of Norse pictograph stone carvings, some dating as far back as the fifth millennium CE.
The spirits ship is most commonly found on funerary monuments, where it represents the journey to the afterlife. The symbol has obvious connections to the Viking practice of sending the deceased into the afterlife aboard a burning ship.
Interestingly, the form of the boat in the ancient carvings is identical to the Viking longship. Similar carvings have been found in Canada, dating as far back as 800 BCE.