The magnificent Fontana dell' Acqua Paola (1608-12), which is also known simply as Il fontanone (the big fountain), was commissioned by Pope Paul V (r. 1605-21), and designed by Giovanni Fontana (1540-1614) & Flaminio Ponzio (1560-1613).
The Fontana dell' Acqua Paola, which was the first major fountain to be erected on the left bank of the Tiber, was fed by the Aqua Trajana, an ancient aqueduct built by the emperor Trajan (r. 98-117). The aqueduct was restored by Pope Paul V and renamed the Acqua Paola. The façade of the fountain is adorned with six granite columns, which support an architrave bearing an inscription that proclaims: ANNO DOMINI MDCXII PONTIFICATVS SVI SEPTIMO (In the year of the Lord, 1612, the seventh year of his pontificate).
The longer inscription reads: PAVLVS QVINTVS PONTIFEX MAXIMVS / AQVAM IN AGRO BRACCIANENSI / SALVBERRIMIS E FONTIBVS COLLECTAM / VETERIBVS AQVAE ALSIETINAE DVCTIBVS RESTITVTIS / NOVISQVE ADDITIS / XXXV AB MILLIARIO DVXIT (Paul the Fifth, Pontifex Maximus, collected this water, drawn from the purest of springs in the neighbourhood of Bracciano, and brought it for 35 miles from its source over the ancient channel of the Aqua Aliestina, which he restored, and over new ones, which he added).
The fountain sports images of a dragon and an eagle, the two creatures which make up the Borghese coat of arms, the illustrious family to which Pope Paul V belonged.