Geffcken Johannes, a Lutheran clergyman of Germany, was born in 1803 at Hamburg. He became in 1829 pastor of St. Michael's church, in his native city, and retained this position until his death, October 2, 1865. He wrote a history of Semipelagianism (Gesch. des Semzipelagiasnismus (Hamb. 1826); on the division of the Decalogue (Ueber die verschiedene Eintheilung des Dekalogus, Hamb. 1838 on the picture catechism of the 15th century (Ueber d. Bilderkatechism, des 15ten Jahrhunderts, Leipz. 1855), and several other works. Allgem. Real-Encyklop. s.v.