Throughout the long and complex performance history of Swan Lake the 1895 edition of Petipa, Ivanov, and Drigo has served as the definitive version from which nearly every staging has been based. Nearly every balletmaster or choreographer who has re-staged Swan Lake has sought to make modifications to the ballet’s scenario, while still maintaining to a considerable extent the traditional choreography for the dances, which is regarded as virtually sacrosanct. Likewise, over time the role of Siegfried has become far more prominent, due largely to the evolution of ballet technique.