The basilica of San Silvestro is halfway between the Roman Theater and the Cathedral of San Giusto, in the district of Cittavecchia, next to the church of Santa Maria Maggiore and a few steps from the Arco di Riccardo. It is currently the place of worship of the Evangelical Reformed Helvetic and Waldensian Communities, but until 1784 it was an important Catholic church and also the oldest church in the city. On the facade there is a rose window above what was once the main door. The church has an irregularly shaped plan without an apse, with a central nave and two minor aisles, the ceiling is trussed. The remains of the frescoes that can still be seen date back to the early fourteenth century and represent scenes from the life of the Emperor Constantine and the Annunciation.

Some members of the Evangelical Community of the Helvetic Confession, mostly Swiss immigrants from Grisons (hence the title of the street facing the façade with the small staircase), bought it and, after having restored it, reopened it to the reformed cult, dedicating it to Christ the Savior .

Due to a violent earthquake in 1927 the church was heavily damaged and was then restored with the initial style of the fourteenth century and, in 1928, became a national monument.