Tang Ruowang came to China to spread Catholicism during the Chongzhen period of the Ming Dynasty. He is proficient in astronomy, geography, mathematics and medicine. At that time, China's calendar had exposed many drawbacks and deviations. For a farming empire like China, an accurate calendar has a great influence on China's production and economy.

Tang Ruowang said.

Tang Ruowang (1592—1666), a native of Cologne, Germany, was a Jesuit missionary. From 65438 to 0620 (forty-eight years of Wanli in Ming Dynasty), he went to Macau and lived in China for 47 years. After Ming and Qing Dynasties, he was one of the most important Jesuits in China after Matteo Ricci.