Question: the Libretto of  Amadis de Gaule was originaly set by an Italian-born French composer, instrumentalist, and dancer who spent most of his life working in whose court? 
Sentence (from "Amadis de Gaule (J.C. Bach)"): Amadis de Gaule, or Amadis des Gaules ("Amadis of Gaul"), is a French opera in three acts by the German composer Johann Christian Bach.
Relevant evidence: Yes