In this illustration, Piranesi created an architecture that resembles in many ways the Colosseum. The space splits into two flanks, one at each side of a moat-like feature on the building’s basement. At the bottom right of the composition, on the lower level of the underground floor, successive structures of massive rectangular stones bear reliefs of lions, alluding to the battles of gladiators and other spectacles in which these animals were raised upward to the arena. Some facts help to justify Piranesi’s reference to the Colosseum. The edifice was and still is a masterpiece of Roman architecture and engineering and carries a highly symbolic significance of Roman power and capability. In this illustration, Piranesi conjures up the masterpiece to celebrate the genius of ancient Romans.
But Piranesi also wanted to promote the magnificence of the ancient Roman legal system in the Carceri series. This plate acts as a reminder of the debates that Piranesi had brought up in Plate II on taste, encompassing not only the arts but also the law. In the eighteenth century, and for Piranesi more than anyone else, law and architecture were two sides of the same token. Piranesi greatly explored the principle that law is a reflex of the degree of development of a civilization for the first time with the Carceri series, and later on with other publications. Just as Piranesi promoted Roman architecture to elevate the aesthetics, so he promoted the lex romana to elevate the ethical parameters of his epoch and to create awareness of the existent flaws in the law. Both justice, the outcome of law, and taste are concepts that encompass the faculty of good judgement. In criticizing a specific code of rules, Piranesi was deploring on the whole culture from which those rules originated. In analogy, the formulation of a fair law, such as those of the Romans, in Piranesi’s opinion, was a sign of moral sophistication and fine culture. In Della Magnificenza ed Archittetura de' Romani, Piranesi textually affirmed that the Roman king Tullus Hostilius (reign 673 – 642 BCE), cited by Piranesi in Plate XVI and whose reign preceded the contact between Greece and Rome, was the major author of civil law.
The Greek influence in Roman aristocracy of the epoch instigated Piranesi's criticism of the first emperors in ancient Rome. For Piranesi, it was the influence of Greece that degenerated Roman values and, ultimately, caused its downfall. The excesses of power and extravagance of the first emperors, namely the ones from the Julio-Claudian dynasty, exposed the impact of Greek influence and were a clear sign of the eminent collapse of that society.
In Plate II, the artist had conjured up, though the representation of busts and plaques, at least seven historical figures that were convicted of treason during late Republic and early Empire. Here, in plate V, following the reference to these enemies of the tyrannical first emperors that ruled over ancient Rome, Piranesi depicts a relief to the left of the illustration showing a detention scene, providing a key element to understand this plate. The man taken by the guards collectively represents the seven martyrs in plate II. Piranesi is denouncing, through these historical events, the arbitrariness and cruelty of the first Roman emperors and, at the same time, proposing a broad debate on taste, arts, and the law.