This large drawing shows the prospect of the Trevi Fountain from a lower vantage point, which results in the fountain acquiring a somewhat compressed effect with the façade of Palazzo Poli appearing wider than it is in reality – among other reasons, because the view is restricted to the edge of the cliff face without the basin or the flight of steps, as though it were an architectural drawing.
The graphic description of the fountain is extremely meticulous in its depiction of the façade's architectural details, while the artist adopts a freer hand in defining the sculptural group and the rocks in the basin.
The sheet of laid paper is glued onto stiff card, which is glued in its turn onto a wooden support. The passepartout and gilded frame are a later addition. The technique involving pen and brown ink with brown and grey watercolouring and the brown watercolouring of the background adopted to impart greater prominence to the subject depicted, the style consisting in strokes in relief with shading for chiaroscuro areas, and above all, certain incongruities in the decorative apparatus compared to the fountain's appearance today, all allow us to date the drawing to the late 1750s.
It is a recorded fact that the Trevi Fountain was designed by Nicola Salvi (a copy of his original design is held by the Museo di Roma, inv. GS 880, dated 1733, pen, ink and watercolour on paper, 395 x 555 mm), and that his design was selected in a competition run by Pope Clement XII Corsini in 1732 on the grounds that it was at once the most monumental design and the design that would cause the least amount of damage to the Conti di Poli's palazzo on which it was to rest, and more importantly, on the grounds that it was the least costly. The monument took a long time to build, and work was frequently broken off due to lack of funds; in fact, it had not been completed by the time Salvi died in 1751. An indication of the progress made in the project's execution may be found in Giuseppe Vasi's etching View of the Unfinished Aqua Virgo Fountain known as the Fountain of Trevi, plate no. 12 in the series entitled Views of Rome on the Tiber, produced in around 1743 (P. Coen, Le Magnificenze di Roma di Giuseppe Vasi, 2006, see ICG FN 22731 - 22744). Behind the wooden scaffolding concealing the construction site, the palazzo's façade appears to have been largely completed, with the four statues of the Seasons on the architrave and with the Corsini pope's crest; the two reliefs and the two statues in the niches to either side are still missing, and of course none of the part with the cliff and the large sculpture group with Ocean has yet been erected. The commemorative inscription dedicated to Clement XII has already been partly carved while the second inscription dedicated to Benedict XIV is missing, though it does appear in our drawing which, however, shows no sign of the third inscription dedicated to Clement XIII.
In the two side niches, the drawing shows the two statues portraying, on the right, the virgin after whom the water is named (the girl who pointed out the source to thirsty soldiers) and, on the left, Marcus Vispanius Agrippa who built the acqueduct that brings the Aqua Virgio to the Pantheon. These were the original ideas in Nicola Salvi's design, which also provided for two reliefs reproducing two anecdotes associated with the Aqua Virgo and linked to the two figures portrayed in the statues (the Roman virgin indicating the source's location, and Agrippa ordering the construction of the acqueduct). The two figures are depicted in this drawing, but in the event, the two statues originally included in Salvi's design were replaced by depictions of Abundance (right) and Salubrity (left), carved by Filippo della Valle after Pope Clemente XIII's election in 1758. Giuseppe Pannini (1720 – 1812), painter and architect Giovanni Paolo Pannini's son, took over as supervisor of the construction work on Salvi's death in 1751 and made a few changes to Salvi's original design, particularly in the central part of the rock where he created three regular basins in polished marble. Our drawing, on the other hand, shows a flight of seven steps with water running down them situated at the foot of the shell acting as Ocean's base, whilst the scupture group carved by Pietro Bracci is far closer to the group currently in place, differing little from the original design. Andrea Bergondi and Giovanni Battista Grossi carved the present reliefs in around 1758. They appear to differ from those depicted in our drawing, not in terms of their subject matter but because they have been executed differently. Grossi's, in particular, which was supposed to commemorate the origins of the Aqua Virgo, so named after a girl, Trivia, who indicated a nearby source to some thirsty Roman soldiers, and its position in the space between the columns on the upper left-hand side of the fountain, had already been defined in the large wooden model made by a carpenter named Carlo Camporese to a design by Giovan Battista Maini and Nicola Salvi in 1735. This model is now in the Museo di Roma in Palazzo Braschi (Pietrangeli, 1971; J.A. Pinto, Il modello della fontana di Trevi, in In Urbe architectus… [catal.], Rome 1991, pp. 70 s.). The composition of the work, for which there exists a plaster model (1.85 x 1.20 mt) built into the third landing of the monumental staircase in Palazzo Rondinini, with few differences compared to the final version, echoes the composition seen in the large wooden model of the fountain.
In a painting by Giovanni Paolo Pannini with a view of the fountain, now in the Boston Museum of Fine Arts, the decorations closely resemble those depicted in our drawing, with the difference that the two reliefs appear to be those currently mounted on the fountain, thus it might be dated immediately after 1758. Here too, as in our drawing, there is no sign of the inscription installed by Clement XIII in 1762 immediately after the fountain was inaugurated on 22 May of that year. Giovan Battista Piranesi's engraving dated 1773, for its part, shows the statues and reliefs as they are today.
In conclusion, this may be a presentation drawing (with the later superimposition of grey-blue tempera and white lead to depict the water) depicting a decorative situation designed but never built in the part of the central sculpture group and the cliff, of the reliefs and of the two statues, which can be dated precisely to the end of the 1750s, but before 1758 when Giuseppe Pannini took over as the construction supervisor.