During the second half of the nineteenth century, the Catholic Church of Europe lost much of its glory after the suppression of the Jesuits of 18th century as well as the implementation of the religion-banning policy during the Yongzheng ruling period of Qing dynasty. In 1840s, of all the Catholic missionaries in Beijing, only four people were still working on the Astronomy Board: Portuguese Caetano Pires, José Ribeiro Nunes , Verissimo Monteiro de Serra, and Domingos Joaquim Ferreira. Later, Domingos Joaquim Ferreira died in 1824; Verissimo Monteiro de Serra returned to his homeland in 1826, and José Ribeiro Nunes died in the same year. Up to then, Caetano Pires, who was already in his sixties, was the only European missionary staying in Beijing. Caetano Pires was afraid that the property of Nant’ang would be confiscated if he passed away, so he entrusted all the land contract and documents to a Russian missionary, whose Chinese last name is Wei （魏）. This clue helps make connections between the Beijing mission of Russian Orthodox and the legacy left by European missionaries in Beijing. Based on the original documents of Legacy left in Beijing by Portuguese Missionary, which are kept in Russian National History Archives, as well as the records left by the Russian Orthodox missionaries, this paper here is to clarify this connection.