The bronze turtles around the upper basin, usually attributed either to Gian Lorenzo Bernini or Andrea Sacchi, were added in either 1658 or 1659 when the fountain was restored.

It carried water from the village of Salone in the Alban Hills, nine miles north of Rome, and ended in a fountain near the Pantheon.

When Pope Paul IV decided to build a wall around the Ghetto in 1555 and imprison the Jewish population, the Mattei were given a key to the gate.

The Ephebes, in the mannerist style, may have been inspired by eight bronze figures made in 1563-1565 by Bartolomeo Ammannati for the Fountain of Neptune, or du Biancone, in Florence.

All of the fountains connected to the Acqua Vergine aqueduct had the same problem- the immediate source of the water, a reservoir near the Piazza Spagna, was only sixty-seven feet above sea level, with only a twenty-three foot fall over the entire system.

Four of the dolphins which were intended to spout water, probably supported by the hands of the ephebes, were removed and moved to another fountain, the Fontana della Terrina, which was then in the Campo de'Fiori, before being moved to a new site in front of the new church of Santa Maria in Vallicella[10] The fountain in Piazza Mattei was left with a single upward jet of water in the vasque which filled the bowl, which drained through the mouths of the puti into the lower basin, and four small streams through the mouths of the dolphins which flowed into the conch shells.

[14] The original fountain design called for four bronze dolphins on the upper vasque, supported by the upraised hands of the four young men.

[15] Probably to correct this problem and balance the composition, the four turtles around the edge of the vasque were added during a restoration of the fountain between 1658 and 1659 ordered by Pope Alexander VII.

The statue was equipped with a water purification system to prevent the buildup of calcium deposits, which had required the frequent cleaning of the fountain.

[20] Other historians note that Roman fountain statuary in the Renaissance usually told a story or represented a virtue which their patron believed he possessed.

The German historian Phillip Fehl suggested that the theme of the fountain was "Festina lente," the neoplatonic saying "make haste slowly," contrasting the speed of the dolphins and the slowness of the turtles.

[21] Norwegian art historian Anne Kristine Togstad believes that the male figures and turtles are both connected to the Roman and Greek legend of Jupiter and Ganymede.

The father was impressed and allowed the marriage to go ahead, and the Duke, to remember the event, had the window overlooking the fountain closed up.

[23] The story is probably only a legend; sceptics note that it would have been very difficult to construct such a complex fountain in the dark without making any noise in a single night.

A replica of the fountain, made in Rome in the early 1900s, was bought by William H. and Ethel Crocker for their estate at Hillsborough, California.

[1] There are four documented replicas of Fontana Delle Tartarughe in the United States, located in Bloomfield Hills, Michigan; Sarasota, Florida; San Francisco, California; and at the Elms mansion in Newport, Rhode Island.

[25][26] The fountain and the Piazza Mattei appear in the 1968 war movie Anzio, when a reconnaissance party enters the city in a Jeep.