ACHTERFELDT, JOHANN HEINRICH. - German Catholic theologian, b. 1 June 1788 at Wesel, d. 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.
Entirely imbued with the doctrines of Hermes, in 1832, together with his colleague Giovanni Guglielmo Braun, he founded the journal Zeitschrift für Philosophie und katholische Theologie, in defence of Hermesian teachings; and in 1834-36, after the death of Hermes, he published his Christkatholische Dogmatik.
Pope Gregorio XVI, on 26 Sept. 1835, condemned Hermes; but A. continued to defend his doctrines, maintaining that the condemned errors were not to be found in his works. Because of this attachment to the doctrines of Hermes, A. was suspended in 1843 and also deprived of his teaching position. After 1860, however, A. was reconciled with the Church; his suspension was consequently lifted, and he died in orthodoxy.