People forget, or just don't know, that besides the Roman Legions being the Delta Force and Seal Team 6 of it's time, they BUILT all these great Architectural and Engineering wonders wherever they went. It wasn't like:
"Okay guys, we've conquered these Barbarians now we'll call in the Architect and Construction Manager while we go off to pillage, burn, and have our way with the livestock.";-)
Very true, the Roman system of roads was constructed for military use, and had the inadvertent effect of producing a transportation infrastructure for commercial activity.