Folia was written soon after Graal théâtre, which is evident in the virtuoso string writing. Saariaho originally intended to rescore her cello work Petals for double bass, but she abandoned this idea because of technical differences between the instruments. In writing Folia, Saariaho worked from the same basic approach as in Petals, but Folia already belongs to a new period, with textures closely related to those of Graal théâtre.