In the last letter that is preserved from Francis Xavier, written from the island of Shangchuan off the shore of China two weeks before his death on 3 December 1552, he expressed his hope of going to China despite the many difficulties involved. It was, however, thirty years before Matteo Ricci (1552-1610) obtained permission for a permanent residence on the mainland (in 1583). The Jesuit presence during the next two hundred years can roughly be divided into five periods, each covering approximately thirty to forty years. The first period, from 1583 to 1616, was the time of the pioneers. It was characterized by Matteo Ricci's activities. Not only did he gradually develop a missionary strategy under the encouragement of the Visitor of Asia, Alessandro Valignano (1539-1606); Ricci was also responsible for an “ascent to Beijing,” a movement from the south to the north and from the periphery to the center. In 1610, at the moment of the death of Matteo Ricci, there were merely sixteen Jesuits in China, eight Chinese and eight foreigners, with around 2,500 Christians. A few years later, in 1616-17, an anti-Christian movement forced the Jesuits to withdraw to the center of the country. Around 1620, when the situation calmed down, a new group of missionaries initiated a second period. These included several Jesuits versed in mathematics or Aristotelian philosophy, among them Johann Adam Schall von Bell (1592-1666). Due to their efforts, Jesuits were involved in large-scale translation activities, of both religious and scientific writings.