Jean-Philippe Rameau; 25 September 1683 – 12 September 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. It was not until the 1720s that he won fame as a major theorist of music with his Treatise on Harmony and also in the following years as a composer of masterpieces for the harpsichord, which circulated throughout Europe. He was almost 50 before he embarked on the operatic career on which his reputation chiefly rests today. His debut, Hippolyte et Aricie (1733), caused a great stir and was fiercely attacked for its revolutionary use of harmony by the supporters of Lully's style of music. Rameau's music had gone out of fashion by the end of the 18th century. Today, he enjoys renewed appreciation with performances and recordings of his music ever more frequent.