Arvo Pärt became one of the great prophets of contemporary sacred music thanks to two things: Gregorian chant and Soviet oppression. The Estonian composer, born in 1935, studied at the Tallinn Conservatory. His modernist credentials were first displayed by scores such as the edgy collage piece “Pro et Contra” and Credo (1968), inspired by verses from St Matthew’s Gospel. In reaction to being interrogated by the authorities to explain the latter work’s “political aim,” Pärt invented a new style of polyphonic composition. His tintinnabuli works, named for their bell-like sonorities, began with “Für Alina” in 1976 and mushroomed the following year with a surge of essential pieces, including “Fratres,” “Cantus in Memory of Benjamin Britten,” “Summa,” and “Tabula Rasa.” After leaving the Soviet Union in 1980 and settling in West Berlin, the composer captured a cult following thanks to Manfred Eicher’s ECM Records. Works such as Kanon Pokajanen, Passio, “The Deer’s Cry,” and “Adam’s Lament” found a mass audience hungry for spiritual experiences yet alienated from religion, leading Pärt to become one of the world’s most frequently performed composers.