In the square by the same name there is a building in white and pink stone dating back to the thirteenth or fourteenth century. It is Gothic in style and has only one nave. The decoration of the façade is not complete. There is a lovely portal on the right side with small columns and a painted lunette. In the inside there are important frescoes and paintings preserved such as the noteworthy chapel of the Magdalene and an eighteenth century painting on cloth by Giovanni Lanfranco. Through a chapel on the inside it is possible to enter the crypt or former church of St. Peter. This is a rectangular area with frescoed walls and vaults resting both on the surrounding walls and a central pillar. The Holy Inquisition probably had its jail in this area which was used as a women's prison until very recently. This area now constitutes an interesting and most particular exhibition venue.