Background: Jean-Philippe Rameau (French: [Zafilip Ramo]; (1683-09-25)25 September 1683 - (1764-09-12)12 September 1764) was one of the most important French composers and music theorists of the 18th century. 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 Francois Couperin. Little is known about Rameau's early years, and it was not until the 1720s that he won fame as a major theorist of music with his Treatise on Harmony (1722) and also in the following years as a composer of masterpieces for the harpsichord, which circulated throughout Europe.
Context: Along with Francois Couperin, Rameau is one of the two masters of the French school of harpsichord music in the 18th century. Both composers made a decisive break with the style of the first generation of harpsichordists, who confined their compositions to the relatively fixed mould of the classical suite. This reached its apogee in the first decade of the 18th century with successive collections of pieces by Louis Marchand, Gaspard Le Roux, Louis-Nicolas Clerambault, Jean-Francois Dandrieu, Elisabeth Jacquet de la Guerre, Charles Dieupart, and Nicolas Siret.  Rameau and Couperin have different styles. They seem not to have known one another (Couperin was one of the official court musicians while Rameau was still an unknown; fame would only come to him after Couperin's death). Rameau published his first book of harpsichord pieces in 1706 while Couperin (who was fifteen years his senior) waited until 1713 before publishing his first "ordres." Rameau's music includes pieces in the pure tradition of the French suite: imitative ("Le rappel des oiseaux," "La poule") and character ("Les tendres plaintes", "L'entretien des Muses") pieces and works of pure virtuosity that resemble Scarlatti ("Les tourbillons," "Les trois mains") as well as pieces that reveal the experiments of a theorist and musical innovator ("L'Enharmonique", "Les Cyclopes"), which had a marked influence on Daquin, Royer, and Jacques Duphly. The suites are grouped in the traditional way, by key.  Rameau's three collections appeared in 1706, 1724 and 1726 or 1727, respectively. After this, he only composed a single piece for the harpsichord: "La Dauphine" (1747). Other works, such as "Les petits marteaux," have been doubtfully attributed to him.  During his semiretirement in the years 1740 to 1744, he wrote the Pieces de clavecin en concert (1741), which some musicologists consider the pinnacle of French Baroque chamber music. Adopting a formula successfully employed by Mondonville a few years earlier, these pieces differ from trio sonatas in that the harpsichord is not simply there as basso continuo to accompany other instruments (the violin, flute or viol) playing the melody but has an equal part in the "concert" with them. Rameau also claimed that the pieces would be equally satisfying as solo harpsichord works--although this statement is far from convincing, since the composer took the trouble to transcribe five of them himself--those where the lack of other instruments would show the least.
Question: Who is the other master?

Answer:
Along with Francois Couperin,