When the via Flaminia was first built, its western branch proceeded north from Narni, sparking the development not only of Carsulae, but also of Acquasparta and Bevagna. This branch of the road courses through a gently rolling upland plain at the foot of the Martani mountain range, an area that had been heavily populated since the middle of the Bronze Age. The original course of the via Flaminia the "western branch" proceeded from Narni to what is now San Gemini, Carsulae, Acquasparta, Massa Martana, Bevagna and Foligno. The later eastern branch proceeded from Narni to Terni, north to Spoleto, then past Trevi and finally to Foligno.