ACHTERFELDT, JOHANN HEINRICH. - German Catholic theologian, born on 10 June 1788 at Wesel, died at Bonn on 11 May 1877. Ordained priest in 1813, in 1826 he became professor of moral theology and homiletics in the faculty of Catholic theology at the University of Bonn.
Deeply imbued with the teachings of Hermes, in 1832 together with his colleague Giovanni Guglielmo Braun he founded the journal Zeitschrift für Philosophie und katholische Theologie to defend hermesian teachings, and in 1834-36, after Hermes' death, he published the Christ-katholische Dogmatik.
Pope Gregory XVI, on 26 September 1835, condemned Hermes; but A. continued to defend the doctrines, arguing that the errors condemned were not to be found in Hermes' works. Because of this attachment to Hermes' teachings, in 1843 A. was suspended and also deprived of his teaching position. After 1860, however, A. was reconciled with the Church, and the suspension was lifted; he died in orthodoxy.