This is how I think it happened.
A designer got a book cover assignment for another book about the wife of Henry VIII. The story is well known, as is the historic painting of the queen which the designer received to use on the cover.
What to do? The designer desperately tried to immerse himself into the subject. As he (or she) tried to find a different angle, he stared into the portrait and asked, “What would Henry VIII do to you? My dear, he would chop your head off.”
And so the trend was born.
It extends beyond historical works on the subject of Henry VIII’s wives to nearly all historical periods, including titles that merely reference history as well as everyday contemporary romantic fiction. It should be noted that in the time of Henry VIII, chopping of heads was not an accurate science. Very often, executioners missed the neck and instead chopped off half of the head. Likewise, as design is not an accurate science, designers do the same sometimes.
See the full “Anne Boleyn” collection—nearly 150 images—on Flickr
All images courtesy of the collection of Mirko Ilic