Diagilev used ballet music which he ordered from composers such as Debussy, Ravel?, Satie, [Richard Strauss]?, Prokofjev?, Poulenc? and others. His choreographer [Mikhail Fokine]? worked it out for ballet. Together they developed a more complicated form of ballet with show-elements and meant to amuse the people instead of aristocracy only. It was a reaction to the romantic period, marked by famous ballet pieces like Sylphide, Giselle and the Swanlake.
In 1910 Diaghilev started a series of ballet seasons in Paris with his Ballet Russes, with famous dancers like [Anna Pavlova]? and [Vaslav Nyinsky]?. The early group around Diagilev swarmed off and founded ballet traditions in the United States ([Georges Balanchine]?) and England (Ninette de Valois and Marie Rambert). Ballet master Serge Lifar revived the Paris Opera.
The end of the nineteenth century brought a development in the treatment of tonality, harmony, rhytm and metrum towards more freedom, Until that time, rigid harmonic schemes had forced rhythmic patterns to stay fairly uncomplicated. But around the turn of the century harmonic and metric schedules had become either more rigid, or much more unpredictable, and each method had a liberating effect on rhytm. This also affected ballet. When Ravel for instance used a 5/4 time in the final part of his ballet Daphnis and Chloé (1912), and dancers of the Ballet Russes rehearsed the part, they sang Ser-ge-dia-ghi-lev all the time to stay in the right rythm.