At some points the water of the Acqua Felice aqueduct system runs underground, which is alluded to in the inscription.

The completion of the Acqua Felice aqueduct now made it possible for Sixtus to approach the replanning of Rome on a citywide scale. At some points the water of the Acqua Felice aqueduct system runs underground, which is alluded to in the inscription on this gate. Under the direction of Domenico Fontana, Sixtus laid out a system of straight thoroughfares, with obelisks at their ends as visual guides, linking Rome's principal churches. This city gate was part of that building campaign.