While satisfying the curiosity of the Kangxi Emperor, especially about physics, medicine, and the history of Europe, he argued that the scientific culture of the West was due to Christianity.
In the Lettres édifiantes, he has written on the admirable example set by the princes of the Sounou family, whose conversion, begun by Father Suarez, he completed.
He demanded services of more tangible importance, notably at audiences granted to the ambassadors of Russia and Portugal during the long negotiations, both commercial and political, with the former of the two powers.
The Chinese ministers needed the missionaries, not only as conscientious and trusty interpreters, but men capable of informing them on European matters and of inspiring confidence.
[1] Parrenin translated into Manchu for the Kangxi Emperor several of the works published in the Mémoires de l'Académie des Sciences at Paris.