The site on which the oratory stands was part of the ancient parish cemetery of Santa Maria in Trastevere, which functioned as such until the start of the 19th century. The French occupiers then banned burials within the city walls, and opened the large new cemetery at Campo Verano.
The oratory was designed by Domenico Servi (his only work in Rome), and built in 1819 for the Pia Unione di Maria Santissima Addolorata e delle Anime del Purgatorio. This was a secular parish confraternity founded in the 18th century to pray for the souls in Purgatory, and was initially based at Santissimo Crocifisso nel Cimitero di Santo Spirito.
Servi made use of existing buildings in the project, which the confraternity had acquired for its meetings in 1787.
There was a restoration later in the 19th century, when the campanile was added and the Pietà on the street frontage changed. By then, the pia unione had become an Arciconfraternita.
After falling out of use in the mid 20th century there was a restoration of the fabric in 1992, and the oratory is presently used by the Community of Sant’Egidio. The diocese now lists it as a church.
The frontage is unusual, having two façades rendered in pink with architectural features in white.
The left hand façade has the entrance, with the former confraternity premises above. There is a molded doorcase, over which is a simple blank tablet sheltered by a floating cornice. Over this in turn is a blank frieze, on which is a large lunette window framed by an arc springing from the frieze. Above the window is a string course, and above that is a horizontally oval window just below the horizontal roofline.
The right hand façade is gabled, and has a pair of sort-of Doric pilasters at its corners supporting a triangular pediment with a broken cornice. Into the tympanum of this intrudes a large blind arch in white, joined to the broken ends of the cornice by lengths of blank frieze. This arch stands on a length of floating cornice, and encloses a smaller arch with a molded frame containing a representation of the Pietà of Michelangelo. This is an object of popular devotion, but was not
the original icon which represented a Calvary. Below the Pietà is a tablet reading Mater Dolorosa ora pro nobis, the frame of which looks as if it is in cipollino marble.
Below the arch cornice is an interesting feature, consisting of a grille with a frame in marble, the side panels inlaid with verde antico. It has worn inscriptions at top and bottom, reading Qui transitis in via, attendite et videte ("You who pass in the street, look and see") and Mortuos honora, fac eleemosynam ("Honour the dead, give alms").
There is a little campanile, in brick with two bell-openings side by side topped by a triangular pediment.
The simple rectangular interior has a single altar, with a crucifix as an altarpiece