Jewish settlers are documented in China as early as the 7th or 8th century CE, but may have arrived during the middle of the Han Dynasty, or even as early as 231 BCE. Relatively isolated communities developed through the Tang and Song Dynasties (7th to 12th centuries CE) all the way through the Qing Dynasty (19th century), most notably in the Kaifeng Jews (the term "Chinese Jews" is often used in a restricted sense to refer to these communities). By the time of the establishment of the People's Republic of China in 1949, few if any native Chinese Jews were known to have maintained the practice of their religion and culture. In the late 20th and early 21st centuries, however, some international Jewish groups have helped Chinese Jews rediscover their heritage.