The first Chinese immigrants usually remained faithful to traditional Chinese beliefs, which were either Confucianism, ancestral worship, Buddhism or Daoism, while others adhered to various ecclesiastical doctrines. The number of Chinese migrants who converted to Christianity remained at first low. They were mainly Protestants who had already been converted in China where foreign Christian missionaries (who had first come in mass in the 19th century) had strived for centuries to wholly Christianize the nation with relatively minor success. Christian missionaries had also worked in the Chinese communities and settlements in America, but nevertheless their religious message found few who were receptive. It was estimated that during the first wave until the 1882 Chinese Exclusion Act, less than 20 percent of Chinese immigrants had accepted Christian teachings. Their difficulties with integration were exemplified by the end of the first wave in the mid-20th century when only a minority of Chinese living in the U.S. could speak English.