The Forum Boarium is regarded as the oldest market in Rome. It dates from the beginning of the 6th century BC. Once used to be a cattle market.
The forum is located between the Palatine Hill and the Capitoline Hill, just by the River Tiber. Because of its flat surface it was used by Romans not only as a market, but also as the main river harbour (Port Tibernius). What is more, it is also a place where the first gladiatoral fight documented in ancient manuscripts took place.
There are two buildings located in the forum, which come from the republican period of Rome. Their construction is considered to begin in the 2nd century BC. The buildings are regarded as the best preserved monuments from those times. The Temple of Hercules Olivarius had been mistaken for the Temple of Vesta for many years. It was erected for the patron of traders of olives and olive oil as a votive offering. The temple is a major example of a building type called peripteros - a sacral building of circular plan surrounded by a single colonnade. During medieval ages the temple was converted into a catholic church. The second building was dedicated to Portunus. He was an apparition whose task was to take care of river and sea harbours - the building was built in that place because of the closeness of the river harbour. Today, interiors of neither of temples are open to the tourists. Unfortunately, the Forum Boarium is usually ignored by tourists who pass it by because of the lack of time.
The Mouth of Truth (Bocca della Verita) is a marble medallion placed near the Forum Borarium. It is the one to attract most of the tourists to that area. Its diameter is 175cm. There is a picture of a deity depicted as a bearded old man. It is probably 2000 years old and is located in a vestibule of the Santa Maria in Cosmedin church.
There are many theories about a function of the medallion. It is also not proven whose image is depicted in it. It is assumed that it could have been used as a cover of a water container or an entrance to an ancient aqueduct. Another theory says that it used to be an element of a fountain. Researchers speculate that the depicted deity can be Mercury, the Roman god of trade and thieves. The supporting fact is a presence of a water spring of Mercury nearby, the place where merchants and offenders used to come to ask for forgiveness for their sins. They also assume that it could be the faun, the god of fertility pictured as a half-man, half-goat. Some assert there are horns on the medallion. Others are convinced it is Jupiter, the father off all gods according to the Roman mythology. They back up that thesis with an existing temple of Jupiter located not far from there. The medallion is supposed to have been a place of swearing an oath.
There is a medieval legend saying that a person who tells lies while keeping a hand inside the Mouth is bound to loose it. The story might have come into being because of the executions of people accused of false hood or betrayal, which took place by the medallion in medieval times. They were sentenced to cutting a hand off.
The Mouth of Truth became popular all over the world because of the movie "Roman Holiday". The journalist (Gregory Peck) showing Rome to a runaway princess (Audrey Hepburn) took her to the oracle, what was a kind of irony, because both of them were lying about their descent and intentions.