Eventually American artists who were working in a great diversity of styles began to coalesce into cohesive stylistic groups. The best known group of American artists became known as the Abstract expressionists and the New York School. In New York City there was an atmosphere which encouraged discussion and there was new opportunity for learning and growing. Artists and teachers John D. Graham and Hans Hofmann became important bridge figures between the newly arrived European Modernists and the younger American artists coming of age. Mark Rothko, born in Russia, began with strongly surrealist imagery which later dissolved into his powerful color compositions of the early 1950s. The expressionistic gesture and the act of painting itself, became of primary importance to Jackson Pollock, Robert Motherwell, and Franz Kline. While during the 1940s Arshile Gorky's and Willem de Kooning's figurative work evolved into abstraction by the end of the decade. New York City became the center, and artists worldwide gravitated towards it; from other places in America as well.