During my last visit to the Manuscript Department of the St. Petersburg Branch of the Institute of Oriental Studies in summer 1998, due to the courtesy of the keeper of Manchu holdings, Dr. Tatyana A. Pang, I could make acquaintance of a trilingual document written in Manchu, Chinese, and Latin (call number С 31). It is probably the original letter, sent by the Emperor Yongzheng to Pope Benedict XIII, in reply to his letter of congratulations on occasion of Yongzheng's accession to the throne. The circumstances that surrounded the dispatching of the letter are a well-known chapter in the history of Missionary relations between the West and China. They have been exhaustively summarised by Antonio Sisto Rosso already in 1948…