The Frenchman Jean-Philippe Rameau was one of the most important music theorists in the history of Western music. He introduced the term of the"subdominant" and divided chord structures into triads (chords with three notes) and tetrads (chords with four notes), and laid the foundation for the modern study of harmonics. Yet, he was also a seminal composer, and his contribution to the development of opera should not be underestimated. In the first 40 years of his life, Rameau remained in obscurity as an organ player in the country side of France. In 1722, he moved to Paris, where he published his Traite de l'Harmonie (treatise on Harmony). Here, Rameau was recognised as a major music theorist and teacher, and soon he would achieve fame as a harpsichordist and composer. Yet, Rameau had even greater ambitions. He desired to become an opera composer. His first operas Hippolyte et Aricie, Castor et Pollux en zijn opera-ballet Les Indes Galantes became huge hits. The music was harmonically a lot complexer than the audience of the time was used to, yet it was also more dramatic. Rameau received financial support from the fabulously rich La Pouplinière and his ties with the royal court. Around 1750, Rameau was at the peak of his fame and his works were being performed throughout France. However, he slowly lost the support of the philosophers and artists of the Enlightenment and after his death in 1764 his operas went into oblivion. Only in the last couple of decades, his music was rediscovered and Rameau gained the attention he deserves.