Ghost of a flea

A book published in Italy by George Ferzoco, director of the centre for Tuscan studies at the University of Leicester, argues that at least two of the women in the porno-erotic wall painting are sorceresses. "I have no doubt that this is by far the earliest depiction in art of women acting as witches," he said.

The 13th-century mural was discovered four years ago at Massa Marittima, a town south-west of Siena. Dr Ferzoco believes it was intended as a warning, by supporters of the papacy, of the anarchy and licentiousness that would supposedly engulf the town if it fell into the hands of their political rivals.