Du Halde lived in China for nearly 30 years. This work recounts the story of Candida Xu, who collaborated with the Jesuit astronomers as had her grandfather, Xu Guangki. For a foldout map of China, du Halde drew upon the Kangxi atlases of 1717 and 1721. Around 1688, at the instigation of the Emperor Kangxi, Le Comte and a dozen other Jesuits began a 30-year project to map the entirety of China. They plotted longitude and latitude coordinates for more than 600 locations based on the meridian of the Paris Observatory. As a result, for the rest of the century both Chinese and European geographers had access to maps constructed from the same geographical data.