The polygonal walls found in Bellagra could be the proof that this municipality stands on the place where once the ancient Vitellia was founded, probably by the Aequi or the Hernici, that later was to become a Roman colony.

In Bellagra there are in fact polygonal walls of the “first kind”, meaning the rougher sort, made up of large blocks that are not very tightly packed and often have smaller stones filling the gaps. These date back to the 7th and 6th C. B.C., while those of the “third type” (3rd and 2nd C. B.C.) that can be admired in Piazza San Sisto, are made out of very tight fitting stones arranged in parallel lines.