Oratorio.

An oratorio is a large musical composition including an orchestra, a choir, and soloists. Like an opera, an oratorio includes the use of a choir, soloists, an ensemble, various distinguishable characters, and arias. However, opera is musical theatre, while oratorio is strictly a concert piece—though oratorios are sometimes staged as operas, and operas are sometimes presented in concert form. In an oratorio there is generally little or no interaction between the characters, and no props or elaborate costumes. A particularly important difference is in the typical subject matter of the text. Opera tends to deal with history and mythology, including age-old devices of romance, deception, and murder, whereas the plot of an oratorio often deals with sacred topics, making it appropriate for performance in the church. Protestant composers took their stories from the Bible, while Catholic composers looked to the lives of saints. Oratorios became extremely popular in early 17th century Italy partly because of the success of the opera and the Church's prohibition of spectacles during Lent. Oratorios became the main choice of music during that period for opera audiences.

1650–1700

During the second half of the 17th century, there were trends toward the secularization of the religious oratorio. Evidence of this lies in its regular performance outside church halls in courts and public theaters. Whether religious or secular, the theme of an oratorio is meant to be weighty. It could include such topics as Creation, the life of Jesus, or the career of a classical hero or biblical prophet. Other changes eventually took place as well, possibly because most composers of oratorios were also popular composers of operas. They began to publish the librettos of their oratorios as they did for their operas. Strong emphasis was soon placed on arias while the use of the choir diminished. Female singers became regularly employed, and replaced the malenarrator with the use of recitatives.