During the Fifth Comintern Congress, Grigory Zinoviev condemned for "revisionism" the works of Georg Lukács, "History and Class Consciousness" (1923) and of Karl Korsch, "Marxism and Philosophy". "History and Class Consciousness" was disavowed by its author, who made his self-criticism for political reasons (he thought that, for a revolutionary, being part of the party was the priority). It became however a leading source of Western Marxism, starting with the Frankfurt School, and even influenced Heidegger's "Sein und Zeit" (1927). Lukács then went to Moscow in the beginnings of the 1930s where he would continue his philosophical studies, and returned to Hungary after World War II. He then took part to Imre Nagy's government in 1956, and was closely watched afterwards.