An important factor for concert hall development in Italy are oratorios built adjacent to large churches. Although used primarily for religious services, these often included organ, choral, and instrumental music. The structures were much smaller than churches, which contributed greatly to their excellent acoustics as compared to their parent cathedrals. Other important features include rectangular shape, high ceilings, and placing organ, choir, and altar in a single acoustical air volume. Many oratorios, especially those in Palermo have upper wall surfaces covered with elaborate sculptures. Few music rooms anywhere had such effective sound diffusers. The lower side walls were normally of wood paneling, but when plaster, were covered with Damask. The excellent acoustics of these oratorios provided a stimulating environment for the development of music in Italy. The word oratorio as applied to musical compositions derives from these halls, especially that used by Philip Neri near Chiesa Nuova in Rome. Neri's pioneer compositions stimulated the development of choral and instrumental music throughout Italy, while the architecture of the oratorio played a decisive rôle in the evolution of excellent concert halls in Italy.