@clacke I've just checked¹ and in 1861 Pontecorvo already had ~9k inhabitants, and since then it didn't have a big growth like other Italian communes, so maybe it was at least already around this “big” in the time of the principate.
Looks like a perfectly reasonable size for a mostly independent entity inside geographical Italy :D
What? we're not in the 12th century or whereabouts? details :D
¹ it.wikipedia.org/wiki/Pontecor… (in Italian, but it's a graph)