It was so named because it contained a relief of the Madonna etched on a lead plate, attributed to Sperandio Savelli, that had gained veneration.
There is also a legend that in the first years of the 16th century the icon had been discovered by youths playing here, near the city walls, and this led to the first chapel, then church.
After the Napoleonic occupation, the members of the company who owned the oratory had the structure deconsecrated and the contents sold off to antiquarians.
The main exhibits are divided into 5 eras: The Museum houses a library of documents and an archive of diverse items from the period.
The initial founding of the museum focused on the patriotic events leading to Italian sovereignty and union.