The links below examine the fascination with severed heads in history, myth, and literature; the first link is an article, and the second link is a collection of fun facts and interesting trivia.
Guillotines and Body Transplants: the Severed Head in Fact and Fiction
Bonehead Trivia:The Skull and Head in History and Folklore
Right: The severed head of Medusa,
as painted by Rubens.