Louis Couperin
Unmeasured preludes for harpsichord started appearing around 1650. Louis Couperin is usually credited as the first composer to embrace the genre. Couperin wrote unmeasured preludes using long groups of whole notes, and these groups were connected by long curves. This kind of notation is found in Couperin's unmeasured preludes and was also done by Élisabeth Jacquet de la Guerre. Another important contribution to the development of the genre was made by Nicolas Lebègue, who used diverse note values in his unmeasured preludes. The first ever published unmeasured preludes appeared in Lebègue's "Le pieces de clavessin" in 1677.