During China's Cultural Revolution, Sidney Rittenberg, an American citizen, became the most important foreigner in China since Marco Polo. Arriving as a GI interpreter at the end of World War II, he was the only American citizen to become a member of the Chinese Communist Party, and was an active participant in the Chinese communist revolution and its aftermath. An intimate of the Party's leadership, including Mao Zedong and Zhou Enlai, he gained prominence at the Broadcast Administration, one of the most important agencies of government.