Voltaire wrote three categories of librettos : 1. three « tragédies en musique » ; 2. two occasional works, a « comédie-ballet » and a « fête » for the court ; 3. an « opera buffa » and an « opéra-comique » for the « Comédie-Italienne ».
In these works, he manifests the principal ideas of the Enlightenment, including his own anticlericalism, and he appeals to the king and the aristocracy to be models of enlightened clemency. The model offered by Metastasio is highly relevant for Voltaire's « fête » and also, in some way, for his tragedies.
The article also discusses several technical problems such as the issue of « canevas » (a metrical pattern suggested by the composer), the number of arias, monologues, ensembles and choruses, certain specific poems, etc.
