After a long and revealing voyage into Piranesi’s Imaginary Prisons, we finally land on plate XVI, the grand finale of the series. In the Carceri, Piranesi created a narrative that chronologically started by the regal period in plate XVI, passed by the transition of the kingdom to the republic, and continued in plate II, with late republic and the first emperors. He acutely cited specific episodes of ancient Rome’s history to support his arguments for the superiority and autonomy of ancient Rome over Greece and to illustrate the disastrous impact of the Greek culture in Rome.
With these references, Piranesi invites his audience to meditate on the values that the different political systems of Rome presented and to build an analogous analysis of their own time. He wants to prove that as much as ancient Rome succumbed to the Hellenist culture, so was modern Rome succumbing to the philhellenism of authors such as Allan Ramsay (1682-1731), Julien-David Le Roy (1724 – 1803), and Johann Joachim Winckelmann (1717 – 1768). By commemorating the magnificence of engineering, architecture, and the law in ancient Rome, Piranesi wants to show the sophistication of that civilization, which achieved an unprecedented degree as early as the regal period. The first historical episode he mentions to make this argument is the trial of one of the Horatii brothers. Piranesi not only depicted the scene as reliefs in the capital of the column to the right of the plate but also incised Horatius’ capital punishment verdict INFAME SCEIVSS … RI INFELICI SUSPE…. ("Hung him on a barren tree"). In Ab urbe condita libri, Livy tells that, after heroically conquering Alba Longa in the Horatii brothers’ duel against the Curatii, the only surviving Horatius was received in Rome with a triumphal march. During the march, he saw his sister Camilla who, secretly engaged to one of the killed Albans, mourned over the death of her fiancé, one of the defeated enemies. Interpreted as an act of treason, he immediately assassinated her and was sentenced to death. The convict’s father appealed the tribunal’s verdict. King Tullus Histilius (reign 673 – 642 BCE) did not want to have the patriotic hero killed either, delegating the case to the people of Rome through the curia. Due to Horatius’s virtue and to the "justifiable" reason for the crime, the sentence was not executed. Instead, the people decided that Horatius would, in lieu of the death penalty, have a symbolic punishment by passing his neck beneath a wooden beam, named Sororium Tigillum or Tigillum Sororis.
Scholars had pointed to the mysterious wooden beams to the right of the plate XVI as the Sororium Tigillum. Similar features, nonetheless, appear in many other plates of the Carceri. The spikes that Piranesi added to the beams, causing the impossibility of the "passage of the neck," is a metaphor for the obstruction or lack of true justice in Piranesi’s own time. Piranesi implies that, in the tenebrous environment of the Carceri, in which only partial remains of the glory of the ancient Romans can be found and are often ignored, the application of a fair law is impossible. With this allegory, Piranesi praised the application of justice elaborated with the participation of the people in contrast to the tyranny of a centralized power, as seen in the martyrs he represented in plate II. For Piranesi, it was the exemplary regal regime that saved the heroic Horatius from an unfair death penalty.
In plate XVI, Piranesi also condemned the beginning of the pernicious impact of foreigner cultures, especially from the Greeks, in Rome. The episode of Horatius brings up the message that the apogee of the Roman law, represented by this specific trial, preceded the influence of Greece, brought to Rome through the law of Solon in the subsequent kingdom of Servius Tullius (reign c. 575 – 535 BCE). Piranesi illustrates the presence of the outsiders in Rome with the reference to King Ancus Martius (reign 642 – 617 BCE) and his concern with the "loss of values resulting from the mingling of diverse settlers" in Rome. Using once more a quotation from Livy, in plate XVI Piranesi depicts the words AD TERROREM INCRESCEN AUDACIAE, from when the king ordered the construction of the first Roman prison to "terrify the growing audacity" of Rome’s increasing population. It was the Carcere Mamertino (Mamertine Prison).
The Carcere Mamertino was a subterranean two-story prison with a barred hole on the floor of the upper space. The hole was used to lower the prisoners to the bottom chamber, as well as pass them food and water. Likewise, Piranesi depicted the barred hole in four out of the sixteen plates of the Carceri and thoroughly explored the subterranean nature of the actual Italian prison to create equally subterranean spaces i. In plate VII, Piranesi exposed this characteristic by inscribing the lettering soterranee carceri incise da Piranesi (subterranean prisons incised by Piranesi) into a slab of stone.
In plate XVI, Piranesi provided one more episode to situate the audience in a temporal line. Piranesi cites the transition from the regal to republican period with the two decapitated heads of Titus and Tiberius Junius Brutus, the sons of Lucius Junius Brutus (545 – 509 BCE). Founder of the Republic in Rome, Lucius Junius Brutus not only presided the trial of his sons after their involvement with a conspiracy to restore monarchy in Rome, but also witnessed their torture and execution. The harshness of the law under Brutus and his impiety was a reflex of the Hellenism and the Greek laws of Dracon in Roman territory. Brutus’ inflexibility and cruelty to his own sons, in contrast to Tullus’ reasonableness, was an evidence of the loss of values about which the kings were worried. For Piranesi, the period of the kings and consuls was the most just and elevated in the history of Rome, in that the Greek influence on that period was null.
The wealth of historical references and iconographical features identified in the Carceri series and the many allusions to episodes and figures in Piranesi's own time compose a solid body of evidence against outdated interpretations that read the Imaginary Prisons as the result of hallucinations or impulsive acts by a tormented artist. The prisons gained overwhelming prominence with the Romantic movement in the nineteenth century, becoming probably one of the most recognizable works by Piranesi. However, the Romantic perspective "locked" its interpretation for too long. Drawing on Piranesi’s earlier and meagerly accurate biographies, the Romantics created a venue of inquiry completely detached from the rest of the work of Piranesi. They looked at the Carceri as an outcast in the artist’s opus, in which he has let his disturbed psyche explode in furious creative bursts following neurosis, fever or drug-induced hallucinations. These tales neglect the intellectual, methodical, and analytical approach that Piranesi demonstrated in the rest of his work and also in the Carceri. Although fascinating, the Romantic interpretation is completely incompatible with firstly, Piranesi’s methods and rationale as seen in other works; secondly, the context around the series’ main publications and its two different editions almost ten years apart and; thirdly, with the process of etching per se, which is long, laborious and requires many steps. To disprove the "immediacy" of the illustrations, preparatory drawings in collections around the world demonstrate that Piranesi thoroughly studied the compositions before proceeding to the taxing etching process.
A relentless commitment to the debate on taste and the Greco-Roman controversy traverses the entire series, welding sometimes disparate subjects into a same overarching narrative. It is ironically in the subterranean prisons that Piranesi is completely free to express his innermost anxieties about the contemporary artistic and intellectual scene, as well as release professional resentments and repressed desires. The inversion of concepts and the multiplication of meanings that Piranesi demand from us through the Imaginary Prisons make the unraveling of its forms a seductively hypnotizing experience. The sixteen plates that compose the Carceri disintegrate the boundaries that define a single meaning in an explosion of different associations. Piranesi challenges us to uncover the prisons like we polish a diamond. There are many more facets of this diamond still waiting to shine. After all, the more facets a diamond receives, more light it reflects, and more beautiful it gets.