The church of St. Erasmo stands in a splendid position, suspended between heaven and earth, on a spur of rock overlooking the Terni basin.
It was a Benedictine monastery dependent on Montecassino, perhaps erected in the 12th century on the site of the Cesi Fortress.
It is of Romanesque architecture with an ornate portal and flanked by buttresses.
The interior has a single nave.
