Question: Who did the composer of  Les fêtes d'Hébé replaced as the dominant composer of French opera?
Context: The French musical ensemble Les Talens Lyriques was created in Paris, France, in 1991 by the harpsichordist and orchestral conductor Christophe Rousset.  This instrumental and vocal formation derives its name from the subtitle of "Les fêtes d'Hébé (1739)" an opera by Jean-Philippe Rameau. Les fêtes de l’Hymen et de l’Amour, ou Les dieux d'Egypte is an "opéra-ballet" in three "entrées" and a prologue by the French composer Jean-Philippe Rameau.  The work was first performed on March 15, 1747, at the La Grande Ecurie, Versailles, and is set to a libretto by Louis de Cahusac.  The opera was originally composed as part of the celebrations for the Dauphin’s marriage to Maria Josepha of Saxony.  "Les fêtes de l’Hymen" proved to be a popular work and by the March 1776 it had been performed exactly 106 times.  The librettist, Cahusac, was especially pleased with the ways in which he had succeeded in giving especial import to the supernatural elements of the work—the plot is based on Egyptian mythology—and to allow particular use of impressive large-scale stage machinery, which was much admired by the audience.  The opera contains seven ballets, a consequence of Cahusac’s desire to further integrate dance and drama, which grew from the typical French devotion to ballet, particularly when allied with opera. Antoine-César Gautier de Montdorge (or Mondorge) (17 January 1701 or 1707 - 24 October 1768) was a French man of letters, best known for writing the libretto for Rameau's "opéra-ballet" "Les fêtes d'Hébé" (1739).  Born in Lyon, he moved to Paris, where he worked as a financier (with the title "maître à la Chambre aux deniers du Roi").  He was a friend and neighbour of Rameau's patron Alexandre Le Riche de La Pouplinière and probably met the composer at La Pouplinière's salon.  Montdorge was not identified as the author of "Les fêtes d'Hébé" on any of its printed editions.  It was first attributed to him by Antoine de Léris in the 1763 edition of his "Dictionnaire portatif des théâtres".  Reviewers severely criticised the literary weakness of the work.  The only other opera libretto Montdorge wrote was the one-act comédie-ballet "L'opéra de société" for Jean-François Giraud in 1762.  He described his experience working as a librettist for Rameau in the anonymously published "Réflections d'un peintre sur l'opéra" (1743). Jean-Philippe Rameau (] ; (1683--)25 1683 – (1764--)12 1764 ) was one of the most important French composers and music theorists of the Baroque era.  He replaced Jean-Baptiste Lully as the dominant composer of French opera and is also considered the leading French composer for the harpsichord of his time, alongside François Couperin. Louis de Cahusac (6 April 1706 – 22 June 1759) was an 18th-century French playwright and librettist, and Freemason, most famous for his work with the composer Jean-Philippe Rameau.  He provided the libretti for several of Rameau's operas, namely "Les fêtes de l'Hymen et de l'Amour" (1747), "Zaïs" (1748), "Naïs" (1749), "Zoroastre" (1749; revised 1756), "La naissance d'Osiris" (1754), and "Anacréon" (the first of Rameau's operas by that name, 1754).  He is also credited with writing the libretto of Rameau's final work, "Les Boréades" (c. 1763).  Cahusac contributed to the Encyclopédie and was the lover of Marie Fel. Lisis et Délie (or Lysis et Délie) was a one-act pastoral opera with music by Jean-Philippe Rameau and a libretto by Jean-François Marmontel.  The musical score is now lost.  It was scheduled to appear at Fontainebleau on 6 November 1753 as part of the celebrations for the birth of the royal prince Xavier, Duke of Aquitaine.  It was due to form a double bill with the "comédie-ballet" "Les hommes" (words by Germain-François Poullain de Saint-Foix, music by François-Joseph Giraud).  However, it was withdrawn from performance and "La danse", the third "entrée" of Rameau's "Les fêtes d'Hébé", was performed in its place.  The reason given for the work's cancellation was that it was too similar to Rameau's "Daphnis et Eglé", premiered at Fontainebleau on 30 October.  The libretto was published but the music does not survive.  Rameau may have reused some of it in his later operas. Les Fêtes Chinoises is an 18th-century ballet by Jean-Georges Noverre (1727–1810).  The exact date of the ballet's composition is unknown but it was probably created in 1751 for Marseilles, where Noverre was ballet master.  Revivals followed in Lyon and Strasbourg and the ballet was staged in Paris on Monday, 1 July 1754 at the Opéra-Comique, with decors by François Boucher.  "Les Fêtes Chinoises" had little in the way of plot or theme but instead was a series of danced pictures inspired by the "Chinoiserie" designs of the Rococo that embroidered upon descriptions of China by travellers and explorers.  The ballet was Noverre's first great success.  The 1755 London production was completely destroyed by anti-French rioters on the eve of the Seven Years' War. Les fêtes d'Hébé, ou Les talens lyriques ("The Festivities of Hebe, or The Lyric Talents") is an "opéra-ballet" in a prologue and three "entrées" (acts) by the French composer Jean-Philippe Rameau.  The libretto was written by Antoine Gautier de Montdorge (1707–1768).  The work was first performed on 21 May 1739 by the Académie royale de musique at its theatre in the Palais-Royal in Paris. . Les fêtes de Paphos ("The Festivals of Paphos") is an "opéra-ballet" in three acts (or "entrées") by the French composer Jean-Joseph Cassanéa de Mondonville.  The work was described as a "ballet héroïque" on the title page of the printed score.  Each act had a different librettist.  "Les fêtes de Paphos" was first performed at the Académie royale de musique, Paris on 9 May 1758 and was a popular success.  Mondonville recycled material from two of his previous operas for the first two acts, namely "Erigone" (1747) and "Vénus et Adonis" (1752), both originally composed for Madame de Pompadour's Théâtre des Petits Cabinets. "Io"'s unfinished state meant that it was once believed to be Rameau's last opera, but it contains a duet which appears in revised form in "Les fêtes de Polymnie" (1745).  This has led the musicologist Graham Sadler to conclude that "Io" must predate 1745 and that the librettist was Louis de Cahusac, who also wrote the words for "Les fêtes", because French librettists did not borrow from other writers.
Answer: Jean-Baptiste Lully