Johann Gerhard Oncken, a German missionary, born at Varel, Oldenburg, about 1800. During his early life he was a domestic servant. After reaching manhood he visited England, where he married, and subsequently opened a book shop at Hamburg, joined the English Independent church, and became the agent of the Lower Saxony tract society and the Edinburgh Bible society. In April, 1834, with six others, he organized a Baptist church, and became its pastor. In 1835 the American Baptist general convention appointed Mr. Oncken their missionary, and he visited almost every portion of Germany and Denmark. In Hamburg he was several times imprisoned for preaching and baptizing; but after the benevolence of his family and congregation to the sufferers by the great fire of 1842, the Hamburg senate passed decrees commending their conduct, and granting them the privilege of unrestricted worship. From that time Mr. Oncken has been actively engaged in the promotion of his missionary work, publishing editions of the Scriptures for gratuitous distribution, writing and publishing religious tracts and books, establishing numerous churches in Denmark, Switzerland, Prussia, the smaller German states, and Austria, and editing with the assistance of his daughter a religious journal in English, and another in German. He visited the United States in 1852 to obtain means for the erection of chapels.
At the end of 30 years the number of churches connected with the Baptist German mission, and directly or indirectly the fruit of his labors, had risen to 76, and the number of members in communion to 11,289. In connection with these churches were 95 Sunday schools, with 240 teachers and 2,662 scholars. The missions have continued to prosper, and their fruits are found in Poland and southern Russia.