We understand by libretto a written work that is used as a guide for the actors of a film or theatrical work. The libretto is normally composed of the dialogue that such actors have to repeat and interpret and, in addition, indications about positions in the space in which they act (sitting on a chair), movements (entering the room) or information on the stage , environment and others. These indications that are not part of the dialogue are not read or interpreted, they simply serve to facilitate the creation of the scene.
The librettos arose historically with the first theatrical representations, those that arose in Ancient Greece (although for some, they already exist since the Egyptian civilization). The librettos, or these early forms of what we now know as librettos, were written to guide the actors in dialogue and were probably much simpler than the librettos are today. The existence of librettos can be found both in the Middle Ages and, later, in the Modern Era in which William Shakespeare was undoubtedly one of the leading representatives of libretti for plays.
The librettos have a more or less similar form or structure in all cases. They are divided into acts or scenes in which a set of related acts or dialogues take place. In each scene, the location of each character, the environment in which they are found, and other information are clarified, as far as possible, and then proceed to the proper dialogue between the different characters in the play. This dialogue is written clarifying the name of each person who speaks or interacts with the others. In the librettos both the words and the sounds and even the silences should be marked so that the actors can know when to speak and when to remain silent.
