Ancient city
Pollio Fountain
Key answer
A single tall arch rises at the western edge of Domitian Square, and it has been called at least three things in print. Before deciding what it meant, it is worth working out what it is.
Three things, one name
Scholarship separates three distinct items that the name “Pollio” has been stretched across: the apsidal fountain south of the so-called Pollio Building on Domitian Square, the adjacent Pollio monument itself, and the earlier aqueduct built for the city and associated with C. Sextilius Pollio.
They are not the same structure and they do not share a dedication. The aqueduct is a piece of regional water engineering, published in its own right; the fountain is an urban display building at the edge of the upper square.
Why the labels slipped
The literature has used “Pollio Nymphaeum” and “Domitian Fountain” inconsistently for the same apsidal structure, largely because of its position beside the Pollio monument and above the square named for Domitian. The most recent study makes the confusion explicit rather than resolving it by decree.
The honest position on site is therefore to explain the label rather than to defend it: this is the apsidal fountain south of the Pollio Building, whatever your map calls it.
What the architecture shows
The surviving architectural decoration includes vine-scroll ornament that belongs in a Flavian-period architectural context. That places the fountain in a phase when the upper city was being monumentalised, and it is a dating argument drawn from carved detail rather than from a dedicatory text naming a donor.
No source used here allows the statement that Pollio personally dedicated this fountain, and sculptural finds from the area should not be assigned to it as certain fixtures.
Water as public display
What the building did is clearer than what it was called. It presented water — arriving through the city's supply system — as an event, in a basin framed by architecture, at the edge of the square where civic life concentrated. Water was a service and a spectacle at once.
Remember also that the tall arch in today's photographs is the result of archaeological reconstruction and presentation, not a wholly untouched survival.
Standing in front of it, the most interesting question is not which name wins, but why a city put so much architecture around a public tap — a conversation that works best with someone who knows which stones carry the argument.
Common questions
No. The aqueduct associated with C. Sextilius Pollio is a separate water-supply structure published in its own excavation volume. The fountain on Domitian Square is a distinct monument that happens to share the name.