Through Porta Spoletina, the consular Flaminia road leading out of Terni, which it crossed in a south-west north-east direction, continued towards the Somma mountain and, therefore, Spoleto. It was one of the main gates to the city, built during the expansion of the city walls during the medieval period. A stronghold, it is also called the Gate of the Three Monuments in memory of the cenotaphs, that a widespread popular tradition ascribes to Tacitus: the historic Cornelius and the emperors Marco Claudio and Floriano Tacito.
Not far from the Gate the remains of a great Arch of Triumph was found, which seems to have been dedicated to the emperor Domiziano, but all the existing vestiges just outside the city walls were permanently lost during the construction of the Bosco mechanical industry during the early years of the 20th century and whose workshops have recently been reclaimed and reused as the Terni Videocentre (after the relocation of the factory to the industrial area during the 1980s.
Just a short distance from the arch of Porta Spoletina, within the city walls, stands an ancient mill, one of the many oil millstones fed by one of the canals belonging to an extended network around the city.
Just along the road from the gate, along the Flaminia stood the church dedicated to the Madonna della Misericordia: Pope Clemente Vll stopped there to say orations while he was travelling to Ferrara, leaving 100 scudi for charity. On the opposite hill stood the church of Santa Giusta and, further up,the Hermitage called "Vecchia" occupied by cappuccino monks. Above them all stood the parish church of San Bartolomeo, followed, along the edge of the mountain going towards the Somma, by the church of the Concezione and that of San Zenone, which is to be found not far from the Fortress of the same name. Being the first rampart for invading foreign armies marching along the Flaminia towards Rome, Porta Spoletina was continuously under attack. One of the most disastrous for the gate structure was the one by Braccio da Montone's army, who, at the beginning of the 1400s, burnt the gate down and, notwithstanding the citizens of Terni, stole the big iron chain as a war trophy.