In the early 19th century, Western colonial expansion occurred at the same time as an evangelical revival–the Second Great Awakening–throughout the English-speaking world, leading to more overseas missionary activity. The nineteenth century became known as the Great Century of modern religious missions.
Beginning with the English missionary Robert Morrison in 1807, thousands of Protestant men, their wives and children, and unmarried female missionaries would live and work in China in an extended encounter between Chinese and Western culture. Most missionaries represented and were supported by Protestant organizations or denominations in their home countries. They entered China at a time of growing power by the British East India Company, but were initially restricted from living and traveling in China except for the limited area of the Thirteen Factories in Canton, now known as Guangzhou, and Macau. In the 1842 treaty ending the First Opium War missionaries were granted the right to live and work in five coastal cities. In 1860, the treaties ending the Second Opium War with the French and British opened up the entire country to missionary activity.
Protestant missionary activity exploded during the next few decades. From 50 missionaries in China in 1860, the number grew to 2,500 (counting wives and children) in 1900. 1,400 of the missionaries were British, 1,000 were Americans, and 100 were from continental Europe, mostly Scandinavia. Protestant missionary activity peaked in the 1920s and thereafter declined due to war and unrest in China. By 1953, all Protestant missionaries had been expelled by the communist government of China.
For Robert Morrison and the first missionaries who followed him, life in China consisted of being confined to Portuguese Macao and the Thirteen Factories trading ghetto in Guangzhou (then known as "Canton") with only the reluctant support of the East India Company and confronting opposition from the Chinese government and from the Jesuits who had been established in China for more than a century. Morrison's early work mostly consisted of learning Classical Chinese, Cantonese, and Nanjing Mandarin; compiling a bidirectional dictionary based on the 1714 Kangxi Dictionary; and translating the Bible. He was forced to take work with the EIC in order to fund these activities and remain at Guangzhou. In such conditions, his proselytizing was limited to his employees, whom he compelled to attend Sunday services and daily meetings including prayer, Scriptural readings, and the singing of hymns. It took years before Cai Gao was interested in baptism. Nonetheless, as Morrison's first converts—Cai Gao, Liang Fa, Qu Ya'ang—were literate men who also became the first Chinese trained in western printing and lithography, they began to express his message in more effective terms and to print hundreds, then thousands, of tracts.