The "Mouth of Truth" is a worn marble disk with a diameter of 175 cm, from the 17th century. located in the porch of the
Church of Santa Maria in Cosmedin. The face of either an oracle, or a faun, or Triton is carved on it. It was created in the 4th century. BC e. and may have been part of a fountain or the hatch of a Roman cloaca. In the Middle Ages, the "Mouth of Truth" was considered a kind of lie detector. In those days, they believed that if you lie, holding a finger or hand in the deity's mouth, it will bite it off. The Bocca della Verità mask became especially popular after the release of the movie "Roman Holiday", which is why today many tourists seek to see this famous marble medallion.