It is the main delivery tank of the Acqua Felice; and the Acqua Felice was the first new supply of water which Rome had received since the aqueducts had been cut off from the city by Vitiges in 537. The statue of Moses is a colossal blunder. Prospero Bresciano had modelled the curious Sixtine lions which served to support the Vatican obelisk, and the Pope gave him the commission for the principal figure in his great fountain. Contrary to the advice of his friends, Bresciano carved this statue, which was to be his masterpiece, directly from the travertine without any previous modelling-the block lying horizontally on the ground.
When the figure was raised it was found to be not only out of proportion but also out of conformity with the laws of perspective. Its unveiling was greeted by the critical Roman populace with a shout of derisive laughter, so Homeric in its volume and duration that it utterly condemned the artist, who, as a result, fell into a melancholia and died. The present lions, which are of bigio marble, are modern, dating from the days of Gregory XVI (1846). This Pope created the Egyptian Museum in the Vatican and removed thither the original lions, which were of Egyptian origin and had been appropriated for his fountain by Sixtus V-two from the Piazza of the Pantheon and two from the gate of St. John Lateran. The two great points of difference between the Fon-tana fountains and the Amannati fountain on the Flaminian Way are interesting and significant. They are, first, the place of the inscription, and secondly the volume of water. The first point of difference is due to the fact that the Fontana fountains, here and on the Janiculum, proclaim the appearance in the city of a new supply of water. Sixtus V and Paul V had each built a new aqueduct and could announce the fact conspicuously by magnificent inscriptions; whereas Julius III, using a stream of water from an aqueduct already in existence, could only claim the honor of having erected the fountain for the convenience of the public.
His inscription, therefore, is not borne aloft on triumphal arches but occupies a place in the central niche, filled in Sixtus V’s fountain by the figure of Moses, and in Paul V’s fountain left absolutely vacant. The stream which Julius III dared appropriate from the Virgo Aqueduct was only large enough to fill a single basin placed before the central niche of Amannati’s fountain; whereas in the Fontana fountains the water fills the entire space below the mostra, as it was naturally the intention to show the magnitude and force of the new supply.