Beginning in the 1940s and continuing to the present day, composers such as Pierre Boulez, Karlheinz Stockhausen and Milton Babbitt have extended the legacy of serialism in increasingly radical directions, while even composers normally considered opposed to Schoenberg's point of view, including Igor Stravinsky, Leonard Bernstein and Aaron Copland, began, in the 1950s, 1960s and 1970s, to explore a