The 1995 Chandos recording of the complete 1993 Requiem remains definitive. Though born a Roman Catholic, Penderecki wouldn't call his Requiem religious music. In the past I have used Hebrew and Russian Orthodox Church music but my main inspiration is the solid German 19th century symphonic tradition and Renaissance polyphony. Despite the historical and patriotic significance of the Polish Requiem, Penderecki denies it is a political piece. I don't write political music.
Political music is immediately obsolete.
My Threnody for the Victims of Hiroshima remains important because it is abstract music. The Requiem is dedicated to certain people and events, but the music has a broader significance. Stylistically the Polish Requiem bears little relation to Penderecki's wild years of innovation in the 1960s. My Threnody is still avantgarde, but the age of experimentation is over. The Requiem reflects Penderecki's new pluralism.