The instrumental music in operas are:

1. Intro

The so-called intro is the music at the beginning of an opera. The orchestra opens the opera. In previous music, the vocal part will sometimes be added appropriately depending on the situation.

The reason why there is an opening song is not only to tell the audience that the opera is about to begin, but also to remind the plot and pave the way for the plot of the opera later. The scope of opening music includes prelude, overture, etc.

2. Intermezzo

In opera instrumental music, in addition to the opening music mentioned above, there are also intermezzos, which are played during or between opera acts or scenes. , an instrumental piece played by an orchestra.

The opening music specifically has the following forms:

(1) The Neapolitan school of music in Italy from the late 17th to the early 18th century, with A. The Italian intro composed by Scarlatti has three parts: fast, slow and fast.

(2) The French-style opening music originated by Lully at almost the same period has three parts: slow, fast and slow.

(3) At the end of the 18th century, the first person to use a sonata as the opening song of an opera was Mozart, who called it the "overture".