Fontana delle Naiadi

The Sovrintendenza Capitolina's record for this fountain carries a Rione field and it reads Castro Pretorio - the plainest statement of the rione anywhere in this guide. The Sovrintendenza describes the fountain as the mostra, or terminal display, of the Acqua Pia Antica Marcia, the aqueduct built between 1865 and 1870 under Pius IX. It names Alessandro Guerrieri and Mario Rutelli as the authors, dates the work 1885-1914, and lists granite, travertine, bronze and cement conglomerate as the materials.

The Sovrintendenza records that the pope provisionally inaugurated the aqueduct's display on 10 September 1870, in the Termini area, and that the fountain was then built definitively in what is now Piazza della Repubblica: the architecture by Guerrieri in 1885, temporarily dressed with four stucco lions for the visit of Wilhelm II in 1888. Rutelli was commissioned for the sculpture in 1897 and the fountain was inaugurated in 1901. A first central group in cement, of 1911, was rejected and moved in 1913 to the garden of Piazza Vittorio Emanuele II; the Glauco clasping a dolphin replaced it and was inaugurated in 1914. The Sovrintendenza records a full restoration in 1998 and another in 2025 under the PNRR - Caput Mundi programme.

Turismo Roma names the four nymphs and their creatures: the Nymph of the Oceans with a sea-horse, of the Rivers with a water-snake, of the Lakes with a swan and of the Subterranean Waters with a lizard. Turismo Roma alone describes the rejected central group as three tritons, a dolphin and an octopus.