Program music is a type of instrumental art music that attempts to musically render an extramusical narrative. It is contrasted with absolute, or abstract, music, which is music that is written for its own sake. Program music might attempt to mirror an existing story from a book or play through sound, or it might evoke a more general scene from nature. The concept of program music does not represent a genre in itself but rather is present in varying degrees in different works of music. The most famous examples of program music are from the 19th century, when the Romantic period saw composers writing increasingly expressive pieces inspired by external stimuli. Some examples of program music include symphonic poems, concert overtures, incidental music, and program symphonies. Program music is often used in film scores and operas, and some film scores have even found a place in the classical concert repertoire.