In 1596 Xu was introduced to Catholicism when he met the Jesuit Lazzaro Cattaneo in Guangzhou, and in 1600 he visited Matteo Ricci in Nanjing. He visited the Nanjing compound again in 1603 to learn Christian doctrines and was baptized “Paul” by the Jesuit missionary Joao de Rocha. In 1604 he sat for the highest examinations in the country and was appointed to the Hanlin Academy. He became a high-ranking government magistrate in Beijing, having studied mathematics under Ricci, and jointly translated The Principles of Calculus, as well as books on hydraulics, geography, and astronomy. In 1607 Xu invited Cattaneo to Shanghai. He built a small church beside his home. In about two years, mainly through the persuasion of Xu, there were 200 new members. When Xu returned to Beijing in 1610, Ricci had died of illness. Xu moved to Tianjin and continued to learn European science from Sabbatino De Ursis and other Jesuit missionaries.
In 1616, when the magistrate Shen Que of Nanjing wrote to Emperor Wan Li to complain about the missionaries, accusing the Jesuits of harboring wrong motives in China and requesting their expulsion, Xu wrote a beautifully crafted, lengthy letter in their defense which became classic reading for Chinese Catholics. He stated the Jesuits were “the disciples of the holy sage, their way is right, discipline strict, knowledge vast, understanding deep, hearts pure, opinion firm, and in their own country, they excelled above most people.” He noted that the doctrine of the Catholic religion they preached has “serving God as its foundation, saving souls as its goal, practicing love and kindness as its method, changing evil to good as its way, repentance as its discipline, blessing in heaven as the reward of doing good, eternal punishment in hell for doing evil, that all their teaching and precepts are the best according to both the principle of heaven and humankind, helping people to do good and shun evil with sincerity.” Xu also suggested the way to accommodate the missionaries and how the Chinese magistrates should govern them. Xu’s brief received the imperial stamp “noted.” The influence of his letter was reflected in the fact that no action was taken by Emperor Wan Li following the submission of Shen Que’s first brief. (Of the 13 Jesuit missionaries in various localities, only four were deported to Macau and nine were able to escape harm mainly because of their defense by Xu, Li Zhizao, and Yang Tingjun).
On 21 Jun 1629, when the Calendrical Bureau of China failed to predict the exact date of an eclipse, Emperor Chong Zhen decided to revise the calendar and entrusted Xu with the task. He was assisted in correctly predicting the eclipse and revising the calendar by three missionaries trained in calendrical matters: Johann Terrenz (Deng Yuhan), Giacomo Rho (Lo Yage), and Johann Adam Schall von Bell (Tang Ruowang). Xu also helped the missionaries translate Christian books. Among the many writings and articles Xu left behind was the Encyclopaedia of Agriculture. In 1933 and 1983, academicians in China and the Chinese Catholic Church held various memorial services and published commemorative books in his honor. Xu was buried in Xujiahui in Shanghai Nandan. In 1983, 350 years after his death, the local government erected a marble statue in front of his grave and opened a park named after him, the Guangqi Garden.
This article is reproduced, with permission, from A Dictionary of Asian Christianity, copyright © 2001 by Scott W. Sunquist, Wm. B. Eerdmans Publishing Co., Grand Rapids, Michigan. All rights reserved.
- Xu’s collected writings are found in Hsu Kuang-chi, Zending Xu wending gongji (1933). Dunne, George H., Generations of Giants (1962), pp. 98-100, 208-15, 222-25. Standaert, Nicholas, Yang Tingyun: Congucian and Christian in Late Ming China (1988), pp. 35-37, 92-94. Xi Zezong, Xu Guangqi Yanjiu Lunwenji (collected essays on Xu) (1986).