Baroque
Around 1600 a new form of theatre with sung text developed in Italy. This genre was originally quite diversely named, from “favola” and “tragedia musicale” to “drama in musica”, but from the 18th century it received the name “opera”.
Music in theatre was not new, but the combination of song, drama and spectacle was. The new genre perfectly embodied the new Italian style which conquered Europe: the baroque, in the sense that opera was the most baroque of all musical genres. The expressiveness as well as the presentation were undoubtedly overwhelming: castrati interpret their deepest emotions in previously unheard, long melodies while theatrical machines surprise the public with new visual effects. More baroque than opera is impossible, thus it should not come as a surprise that Italian opera conquered Europe.
In a time when there were no recordings available, people searched for a way to keep their memories alive. This is why the text of an opera, the libretti, where published. The better libretti also contained illustrations of the set designs. For those who could read music, the music was also published, not the whole score and also not the recitatives, just the “famous airs”, the musical high-points and these only with basso continuo or a piano reduction. In this way the publication was affordable and allowed dilettanti the opportunity to play their favorite numbers and perhaps sing along.