Piranesi’s cathartic release of envy for the architect Luigi Vanvitelli (1700 – 1773), initiated more explicitly in plate XIV, is further explored in this plate. After the publication of the first version of the imaginary prisons in Invenzioni capric di Carceri (1749-50), Piranesi grudgingly witnessed the triumph of Vanvitelli’s "bad taste" in the commission of the Palace of Caserta by the Bourbon king Charles III of Naples. As a parenthesis, Charles III is the same monarch that in the 1740s rejected Piranesi’s engraving for the commemorative publication on the birth of the sovereign’s male heir, Filippo. For Piranesi, the pharaonic palazzo, intended to rival Versailles, was the very concretization of cattivo gusto, including the architect’s aesthetic choices grounded on Baroque, the building’s purpose at service of Absolutism, and the partnership between the monarch and the Catholic Church.
To supply the numerous fountains of Caserta, the palace required a colossal aqueduct comparable in scale to the ones of antiquity. How enticed Piranesi’s imagination might have become with the idea of emulating the great ancient Roman engineers! How might Piranesi had wished to design an aqueduct with his assumed Venetian archaeological and hydrological expertise! In plate XI, Piranesi had already referred to his rival by depicting a shell-like form, the signature shape of Vanvitelli, under the vault to the left of the illustration. Interestingly, the comparison between the first and second editions of this plate reveals that Piranesi considerably darkened the shell on the second edition, metaphorically satisfying his desire to obliterate his rival. Here, in plate XV, Piranesi reproduced the same shell-like forms in the pier at the foreground of the etching. This time, however, he circumscribed a head of an ambiguous form that allude either to a human or a beast’s head within the shell. The resemblance between the face and Vanvitelli’s portrait is, at least, suggestive.
Piranesi also took advantage of the turmoil that involved Vanvitelli’s work on the dome of the Basilica of Saint Peter to mock his adversary. One of the main challenges that Vanvitelli faced as the architect of the Basilica were the fissures of the dome, existent at least since the seventeenth-century. Together with Giovanni Poleni (1683 – 1761), Vanvitelli examined and provided solutions to fix the dome "against the opinions of some of Rome’s most learned scientists." The solution, as Poleni exposed in the justification that Pope Benedict XIV requested, was the use of chains on the base of the dome. The many chains that Piranesi depicted throughout the entire series of prisons, present manifold meanings: they are an expected element to be found in prisons; they are elements that evoke torture and immobility; and they are also a reference to Vanvitelli’s and Poloni’s questionable technical solution for the fissures of the basilica’s dome.
At last, the pier with the singular human-headed-shaped mooring rings, also suggests the form of a cinerarium, especially considering the characteristic framed scene Piranesi depicted at its frontal side. Piranesi had a collection of these objects for sale in his workshop and, therefore, was very familiar with their iconography.