In the years after World War II, de Kooning painted in a style that came to be referred to as abstract expressionism or "action painting", and was part of a group of artists that came to be known as the New York School. Other painters in this group included Jackson Pollock, Elaine de Kooning, Lee Krasner, Franz Kline, Arshile Gorky, Mark Rothko, Hans Hofmann, Nell Blaine, Adolph Gottlieb, Anne Ryan, Robert Motherwell, Philip Guston, Clyfford Still, and Richard Pousette-Dart. De Kooning's retrospective held at MoMA in 2011–2012 made him one of the best-known artists of the 20th century.