Louis Couperin
Keyboard preludes started appearing in the 17th century in France: unmeasured preludes, in which the duration of each note is left to the performer, were used as introductory movements in harpsichord suites. Louis Couperin (c.1626–1661) was the first composer to embrace the genre, and harpsichord preludes were used until the first half of the 18th century by numerous composers including Jean-Henri d'Anglebert (1629–1691), Élisabeth Jacquet de la Guerre (1665–1729), François Couperin (1668–1733) and Jean-Philippe Rameau (1683–1764), whose very first printed piece (1706) was in this form. The last unmeasured preludes for harpsichord date from the 1720s.