By: Giovanni Battista Piranesi
Pope Benedict XIV commissioned engineers Andrea Chiesa and Bernardo Gamberini to prepare a survey of the full course of the Tiber River in order to anticipate problems of flooding and to explore the possibilities for navigation. In addition to the narrative which details this information, there are two maps. The smaller of the maps shows a more detailed view of the Tiber as it passes through Rome. The larger of the two maps, engraved by Giambattista Nolli, is included in four contiguous plates. It includes two vignettes of ruins and many profiles of altitudes of the river. There are also small views of several bridges and other features such as Ponte Molle, Ponte Sant'Angelo with Castel Sant'Angelo, Ponte dei Quattro Capi and Ponte Ferraro. It was only in 1939, that Lamerberto Donati identified that these unsigned engravings in the the Pianta del Corso del Tevere were the work of Piranesi. In fact, they are some of Piranesi's earliest work.
From Piranesi, G. Battista., Wilton-Ely, J. (1994). Giovanni Battista Piranesi: the complete etchings. San Francisco: Alan Wofsy.