"The Swedish missionary Theodore Hamberg (1819-1854) arrived in Hong Kong in 1847 under the Basel Mission and worked with Karl Gutzlaff's Chinese Union. He found that many of its Chinese preachers did not understand the message of salvation, and some were opium smokers who sold their tracts back to the printers; favoring a more careful approach to conversion, he discharged all but a handful of them. He went on to build up a church among the Hakka, instructed Hong Rengan, who was baptized in 1853, and from Hong Rengan's account wrote The Visions of Hung-Siu-Tshuen, and Origin of the Kwang-si Insurrection (1854)."
— Biographical Dictionary of Chinese Christianity
Source: BDCC, "Theodore Hamburg" by Laura Mason (bdcconline.net)