| After the trial of the "Calendar Case" (Yang Guangxian Percecution) during the early Kangxi reign, twenty-five missionaries were sent to Guang Zhou detention. They remained there for five and a half years since March 1666. But very few contributions can show us their activities during this period. We only know from some fragments that they translated the Chinese classics and hold some meetings. But we don't know the details. The main points of this article is trying to analyze thoroughly what the missionaries had done in Guang Zhou detention and its background, to correct some mistakes and misunderstandings on their activities, the change of their number in different stages, the effects of "Canton Conference", etc. The whole article can be divided into four parts: 1) the break-out of "Calendar Case", including its background and reasons; 2) the change of the number of missionaries in different stages; 3) analysis of the activities of the missionaries, which is the most important parts of this research; 4) the conclusion, offering the main ideas of the article. |