In the late sixteenth century, the Congregation of the Filippini (also known as the Oratorians) rebuilt the church of Santa Maria in Vallicella (known as the Chiesa Nuova -new church) in central Rome.
In the 1620s, on a site adjacent to the church, the Fathers commissioned designs for their own residence and for an oratory (or oratorio in Italian) in which to hold their spiritual exercises.
These exercises combined preaching and music in a form which became immensely popular and highly influential on the development of the musical oratorio.

The architect Paolo Maruscelli drew up plans for the site (which survive) and the sacristy was begun in 1629 and was in use by 1635.
After a substantial benefaction in January 1637, however, Borromini was appointed as architect.
By 1640, the oratory was in use, a taller and richer clock tower was accepted, and by 1643, the relocated library was complete.
The striking brick curved facade adjacent to the church entrance has an unusual pediment and does not entirely correspond to the oratory room behind it.
 The white oratory interior has a ribbed vault and a complex wall arrangement of engaged pilasters along with freestanding columns supporting first level balconies.
The altar wall was substantially reworked at a later date.

Borromini’s relations with the Oratorians were often fraught; there were heated arguments over the design and the selection of building materials.
By 1650, the situation came to a head and in 1652 the Oratorians appointed another architect.

However, with the help of his Oratorian friend and provost Virgilio Spada, Borromini documented his own account of the building of the oratory and the residence and an illustrated version was published in Italian in 1725
In the late sixteenth century, the Congregation of the Filippini (also known as the Oratorians) rebuilt the church of Santa Maria in Vallicella (known as the Chiesa Nuova -new church) in central Rome. In the 1620s, on a site adjacent to the church, the Fathers commissioned designs for their own residence and for an oratory (or oratorio in Italian) in which to hold their spiritual exercises. These exercises combined preaching and music in a form which became immensely popular and highly influential on the development of the musical oratorio.
The architect Paolo Maruscelli drew up plans for the site (which survive) and the sacristy was begun in 1629 and was in use by 1635. After a substantial benefaction in January 1637, however, Borromini was appointed as architect. By 1640, the oratory was in use, a taller and richer clock tower was accepted, and by 1643, the relocated library was complete. The striking brick curved facade adjacent to the church entrance has an unusual pediment and does not entirely correspond to the oratory room behind it.  The white oratory interior has a ribbed vault and a complex wall arrangement of engaged pilasters along with freestanding columns supporting first level balconies. The altar wall was substantially reworked at a later date.
Borromini’s relations with the Oratorians were often fraught; there were heated arguments over the design and the selection of building materials. By 1650, the situation came to a head and in 1652 the Oratorians appointed another architect.
However, with the help of his Oratorian friend and provost Virgilio Spada, Borromini documented his own account of the building of the oratory and the residence and an illustrated version was published in Italian in 1725
Francesco Borromini