Lutosławski, one of the major 20th C composers, also worked selflessly on behalf of cultural life in Poland. He only met Szymanowski, a seminal influence, once. Panufnik and Lutosławski, former students together, played piano duos in occupied Warsaw. Copland invited Lutosławski to the U.S., where he also met Babbitt and one of his heroes, Varèse. Rostropovich commissioned a cello concerto, and invited him along with Berio, Xenakis and Dutilleux (a fellow composer-in-residence) to help judge a prize. Britten was a long-standing friend. Lutosławski met Khachaturian in Moscow and Messiaën in Warsaw, and defended Cage against Nono.