The head was considered the most powerful part of the human body.
The Celtic peoples - Irish, British, and Pictish as well as Gaulish - held that the head was not only the place of a person's intelligence but also his emotions and more importantly his soul.
The head of a worthy opponent was taken whenever possible as a symbol of ultimate victory; one warrior had proven so dominant over the other that he now had possession of his soul. In war, these heads would be put on stakes and used as a magical protection of the camp. Otherwise, they might be collected in trunks and shown off to visitors.
The head was a common theme in art as well and stone heads dot the modern landscapes of Britain and Ireland.