The room contains Roman antiquities and there is a section dedicated to the discoveries made in the area of the Vatican. During the royal period and throughout the Republican Age, the area on the right of the Tiber was known as the Ager Vaticanus. It stretched to the north as far as the mouth of the Cremera, and to the south at least as far as the Janiculum. During the Roman Empire, starting from the 2nd cent. AD, the toponym Vaticanum is used to include an area that more or less corresponds to that of the modern Vatican City State. During the Roman period the area lay outside the city of Rome and was occupied by villas, by the gardens of Agrippina - mother of the Emperor Caligula (37-41 AD) - and by many large necropolises flanking the main roads. Caligula built a circus (Gaianum) in his mother's gardens. This was subsequently restructured by Nero (54-68 AD). Various nucleuses of tombs have been excavated along the Via Trionfale, which from St Peter's Square heads north towards Monte Mario. The necropolis which includes the tomb of the apostle Peter, killed during Nero's persecutions and buried here, is along the Via Cornelia, which heads west. His tomb was the destination of pilgrimages and an object of veneration from as early as the 2nd century AD. The necropolis was then buried during the construction of the basilica dedicated to the apostle, desired by the emperor Constantine (306-337 AD), and is now only partly accessible.