The Complex of the Four Fountains is located on the namesake street of Rome, that is, on Via delle Quattro Fontane, at the junction of this street with Via del Quirinale. Originally, they were part of the Acqua Felice aqueduct. None of the four fountains are free standing structures. They are attached to the walls of four distinct buildings which peg out the junction of the two above mentioned streets.
A part of the complex was built between 1588 and 1593, whereas the rest was completed between 1667 and 1669. Muzio Mattei was the one under whose patronage the works carried out in the late 16th century. The impact of the complex on the architectural landscape of the place led to the naming of the church built here later by Francesco Borromini as the Church of San Carlo alle Quattro Fontane (also known as the Church of San Carlino).
The fountains are known after the name of the deity represented on each of them. Thus, the right side of the complex consists of the fountains overtopped by masculine deities: the Tiber River, symbol of Rome, and the Arno River (by most of the accounts), symbol of Florence. They were designed by Domenico Fontana in a superb Late Renaissance style, evoking the monumentality of the ancient classic statues. Domenico Fontana was also the one who designed the statue of Juno which adorns one of the fountains on the left side of the complex. Juno is the symbol of power, but various interpretations see in this work an allegorical statue of Fortitude, with no direct reference to the goddess. The other female figure is construed as Diana, but the symbolism is, again, vague enough to prevent a clear reference to the goddess. The statue on the latter of the four fountains was realized, in all likelihood, by Pietro Berrettini da Cortona.
The fountain of Juno and the fountain of Tiber are, as far as decorations are concerned, embellished with arboreal motifs (added in the 1660s).