[1] The Fontana dell'Acqua Paola was inspired by the popularity of the Fontana dell'Acqua Felice, built in 1585–1588 by Pope Sixtus V. Pope Paul V decided to rebuild and extend the ruined Acqua Traiana aqueduct built by the Emperor Trajan in order to create a source of clean drinking water for the residents of the Janiculum Hill, who were forced to take their water from brackish springs or from the polluted Tiber.

They used white marble from the nearby ruins of the Roman Temple of Minerva in the Forum of Nerva, and constructed a massive gateway of five arches for the arrival of the water.

At the top of the fountain are the papal tiara and keys, above the Borghese family coat of arms of an eagle and a dragon, supported by angels.

[5] Actor Carlo Verdone reminisced on the fact that, growing up in Rome, the expression "you're as good as Acqua Paola water" ("vali como l'acqua Paola") was meant as an insult, the water coming from the lake Bracciano being considered of poor quality back then.

[6] The Latin dedicatory inscription atop the fountain reads: The English line-for-line translation: The American composer Charles T. Griffes wrote a character piece for piano entitled "The Fountains of Acqua Paola" as part of his Roman Sketches, Op.