Ravel orchestrated the piece in 1910.

Pavane pour une infante défunte is a work for solo piano by Maurice Ravel, written in 1899 while the French composer was studying at the Conservatoire de Paris under Gabriel Fauré. Ravel published an orchestral version in 1910 using two flutes, an oboe, two clarinets, two bassoons, two horns, harp, and strings. The Pavane lasts between six and seven minutes and is considered a masterpiece.
The above text from the Wikipedia article "Pavane pour une infante défunte" text is available under CC BY-SA 3.0.