Persephassa is a piece for six percussionists composed by Iannis Xenakis in 1969. The piece was commissioned jointly by the Office de Radiodiffusion Télévision Française (ORTF) and the Shiraz-Persepolis Festival of Arts (presided by the Empress of Iran), held at the historic site of Persepolis (Gluck 2007, 22). The title is one of the variant names of the goddess Persephone / Proserpina, "the personification of telluric forces and of transmutations of life", and also refers to the names "Perseus", "Perceval", and "Persepolis" (Gaillard 1971, 751). It was performed in its premiere by Les Percussions de Strasbourg (France).
Persephassa gains much of its effect from having the six percussionists distributed around the audience. The treatment of space as a musical parameter is one of the most important preoccupations of Xenakis' music, particularly in his works of the mid-to-late 1960s. The dramatic impact of utilizing the performance space in this manner is evident many passages throughout the piece in which accents or imitative rhythms are passed around the ensemble.
The percussionists use a wide range of instruments and sound effects during the piece, including sirens, maracas, and pebbles, along with an arsenal of drums, wood blocks (simantras), cymbals, and gongs.
Pléïades is another Xenakis composition for six percussionists. Composed in 1978, it was commissioned by Les Percussions de Strasbourg.