During the course of time, opera singing has undergone an evolution in style and technique. Let us take just two examples. When the setting for operas changed from chapels or other confined spaces to opera houses, soft, delicate, and effortless singing gave way to singing strengthened by natural body resonators. This transition was accentuated by the shift from the rather modest orchestras used by Mozart to the much larger ones used, for example, by Verdi and Wagner. In the 17th and 18th centuries as well as part of the 19th century, opera music was entirely subordinated to the virtuosity, or technical skill, of the singer. The style that characterized the second half of the 19th century and the first part of the 20th was quite different. In this period, the voice, while still an important part of the opera, became just one of its essential elements.
The potential of opera stimulated extensive musical production. Such composers as Paisiello, Cimarosa, Gluck, Mozart, Donizetti, Rossini, Bellini, Wagner, Verdi, Puccini, Bizet, Meyerbeer, and Mascagni, to name some of the most famous, wrote unforgettable scores capable of stirring deep emotion.