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?
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. The libretto is a revision by Alphonse de Vismes of "Amadis" by Philippe Quinault, originally set by Jean-Baptiste Lully in 1684, which in turn, was based on the knight-errantry romance "Amadis de Gaula" (1508). Bach's opera was first performed at the Académie Royale de Musique, Paris on 14 December 1779. It followed the contemporary French fashion for resetting libretti by Quinault ("Armide" by Gluck and "Roland" by Piccinni are other examples of this trend). The work was not a success with the Parisian public, mainly because it pleased neither the supporters of Gluck nor those of Piccinni, the two leading rival opera composers in France at the time. It was the last opera J. C. Bach composed.
Idomeneo Idomeneo, re di Creta ossia Ilia e Idamante (Italian for "Idomeneus, King of Crete, or, Ilia and Idamante"; usually referred to simply as Idomeneo, K. 366) is an Italian language opera seria by Wolfgang Amadeus Mozart. The libretto was adapted by Giambattista Varesco from a French text by Antoine Danchet, which had been set to music by André Campra as "Idoménée" in 1712. Mozart and Varesco were commissioned in 1780 by Karl Theodor, Elector of Bavaria for a court carnival. He probably chose the subject, though it might have been Mozart. The work premiered on 29 January 1781 at the Cuvilliés Theatre in Munich, Germany.