The Roman baths were a distinctive example of what Piranesi considered the main characteristic of Roman architecture and what made it superior to Greek architecture: its civil and public aim. This etching is the first plate dedicated to the plans of Roman thermal baths which Piranesi included in Le Antichità Romane in order to discuss the results of his research and share his aesthetic theories. In addition to the View of the Seven Remaining Corridors of the Second Floor of the Tepidarium of the Baths of Titus, Called the Seven Halls and the general View of the Ruins of the Baths of Titus, Piranesi here gives a visual idea of the thermal complex by the means of a general plan (“pianta”) or map of the site. As he indicates in many of the plans of the volume, his method of differentiating extant from conjectural elements relies on his etching technique: “La tinta più nera indica la fabrica esistente, la più leggiera ciò, che da me è stato supplito.” Following the work of Andrea Palladio (1508-1580) and other seventeenth and eighteenth-century scholars, Piranesi interpreted the remains of the great thermal site as belonging to the Baths of Titus. Only in 1895 did Rodolfo Lanciani (1845-1929) finally demonstrated that the ruins were those of the adjoining Baths of Trajan (Lanciani 110), built in the second century CE by the famous architect Apollodorus of Damascus (50/60 – 130 CE). In his long discussion in the Index to the Map of Rome, Piranesi challenges what the ancient authors like Tacitus, Suetonius and others said about the sites on the Esquiline Hill and determined what he thought to be the exact location of Titus’ House and Baths which, in his opinion, extended partly into the area of the Gardens of Maecenas (no. 236).

The plan offers an overview and, in its numerical key, identifies specific elements of the thermal site, which was built next to the House of Tito (1, corresponding to the plan of the building positioned on the upper left [the number is lacking on the plan]) and to the Seven Halls (10). A grand staircase (2) led to the upper level. Confronting Piranesi’s plate with the actual reconstruction given by Filippo Coarelli in 2008 and based on the excavations and the existing remains (Coarelli 236-240), it is apparent that Piranesi understood that the Baths had a symmetrical, richly articulated plan, even if he located the built structures in the center of the terraced platform. The main differences between Piranesi's plan and the twenty-first-century reconstruction are the function of the main exedra, which Piranesi interpreted as a theatre (8) and the destination of the central hall: for Piranesi it served as a “cella solare” or sunroom (5), while it was most likely a basilica. 

Beyond the question of accurate identification, what is more striking here is Piranesi’s ability to “read” the ruins: by relying on ancient texts and studying physical remains, he arrives at (and reconsiders) his own reconstruction, in accordance with the knowledge of Roman constructive methodologies and building typologies. In this research, his fervent and tireless imagination gave birth to very personal interpretations as will be later shown in the monumental accomplishment of the Ichnographiam Campi Martii (1762). For this particular etching, an analysis of the copperplate, in which many abrasions and corrections are evident, and a comparison of other versions of the etching taken from earlier editions demonstrate that Piranesi continually elaborated the plan during the years and changed it accordingly to the results of his tireless, ongoing research process. (CS)