Cristóvão Ferreira (c. 1580–1650) was a PortugueseJesuit missionary who famously committed apostasy after being tortured in the anti-Christian purges of Japan. Born around 1580 in Portugal, Ferreira was sent to Asia, where he was a missionary in Japan from 1609 to 1633, becoming the head Jesuit under the oppression of the Tokugawa shogunate. In 1633, Ferreira was captured and renounced Christianity after being tortured for five hours. He became the most famous of the "fallen priests" and changed his name to Sawano Chūan (Japanese: 沢野忠庵). He registered at a Buddhist temple in accordance with Japanese law, and called himself "a member of the Zen sect", but his own publications attest that he adopted a philosophy of natural law:
Viewing the world around we see that everything is endowed with its own nature and merit; bird or beast, insect or fish, grass or tree, earth or stone, air or water, each one has its natural quality and merit. All this is the work of Natura. Man stands at the head of all existence and Heaven has endowed mankind with the natural faculties of charity, justice, propriety, sagacity.
After his apostasy he married a Japanese woman and wrote several books, including treatises on Western astronomy and medicine, which became widely distributed in the Edo period. He also privately wrote a book on religion entitled 「顕疑録」 (The Deception Revealed) in 1636, but it was not published for 300 years. He participated in government trials of other captured Jesuits. He was often present during the use of efumi, whereby suspected Christians were ordered to trample on an image of Jesus Christ. He died in Nagasaki in 1650.