In Greek mythology the Medusa was a creature who was so frightful you could not look at her. If you did, she turned you to stone. Perseus, before he fell in love with Andromeda and freed her from her sea guardian, slew the Medusa while looking at her reflection on his shield instead of directly at her.

The Medusa image was used throughout history as a symbol of the power to scare off the enemy and any evil. Athene wore it on her breast. In painting it on a ceremonial shield, Caravaggio depicted a face with horribly rolling eyes and screaming mouth, distended in a nasty grimace. In all other images too the drive of the expression goes outward, not inward as in the cleaned head in the Capitoline Museums.

After undergoing years of state-of-the-art restoration, the marble sculpture called Medusa and doubtfully attributed to Bernini went on show in December in the centre of a hall of the Capitoline Museums in all its ancient horror and enigmatic beauty.

The carving first surfaced in 1731 in a collection given to the museum by the Sienese marchese Francesco Bichi. His brother Alessandro was a papal nunzio and his other brother Celio, who had been Bichi