Dome

Frontal view of the left portion of the façade; Borromini's finest achievement here is the façade of the oratory hall. This room had special importance for the community because it was there that the form of devotion that typified their Order would be held: a sermon, discussion and exquisitely beautiful choral music. Borromini successfully achieved brilliant decorative effects, carrying on the tradition of elegant brickwork from the Roman Imperial period. The present appearance of the façade was created in several phases. The lower level, completed in 1638, was extended from five bays to seven, and a storey was added to it. In 1665 Arcucci embedded the free-standing gable into a newly added mezzanine floor, thereby diluting the original effect of the gable. Two qualities make the Oratory façade a masterpiece of Roman Baroque architecture: it is concave and has, on the middle bay at the lower level, a small convex projection. Source: Grove Art Online; http://www.groveart.com/ (accessed 12/2/2007)