Caravaggio painted this "Head of Medusa" in 1597 on a ceremonial shield made of canvas mounted on wood frame.
His patron Cardinal del Monte commissioned Caravaggio to paint this subject, and later presented it to Fernando de Medici.
History tells us that Medusa's frighteningly horrible face with snakes for hair, had the ability to turn a viewer's face into stone.

In this picture, the painted shield is encased in a glass case, and seems to scream at the size of the crowd in the room
where it is displayed in the Uffizi.