Karl August von Hase (August 25, 1800–January 3, 1890), German Protestant theologian and Church historian, was born at Steinbach in Saxony. He studied at Leipzig and Erlangen, and in 1829 was called to Jena as professor of theology. He retired in 1883 and was made a baron.

Hase’s aim was to reconcile modern culture with historical Christianity in a scientific way. But though a liberal theologian, he was no dry rationalist. Indeed, he vigorously attacked rationalism, as distinguished from the rational principle, charging it with being unscientific inasmuch as it ignored the historical significance of Christianity, shut its eyes to individuality and failed to give religious feeling its due.

His views are presented scientifically in his Evangelisch-protestantische Dogmatik (1826; 6th ed., 1870), the value of which "lies partly in the full and judiciously chosen historical materials prefixed to each dogma, and partly in the skill, caution and tact with which the permanent religious significance of various dogmas is discussed" (Otto Pfleiderer). More popular in style is his Gnosis oder prot.-evang. Glaubenslehre (3 vols., 1827-1829; 2nd ed. in 2 vols., 1869-1870). But his reputation rests chiefly on his treatment of Church history in his Kirchengeschichte, Lehrbuch zunächst für akademische Vorlesungen (1834, 12th ed., 1900).

His biographical studies, Franz von Assisi (1856; 2nd ed., 1892), Katerina von Siena (1864; 2nd ed., 1892), Neue Propheten (Die Jungfrau von Orleans, Savonarola, Thomas Münzer) are judicious and sympathetic. Other works are: Hutterus redivivus oder Dogmatik der evang.-luth. Kirche (1827; 12th ed., 1883), in which he sought to present the teaching of the Protestant church in such a way as Hutter would have reconstructed it, had he still been alive; Leben Jesu (1829; 5th ed., 1865; Eng. trans., 1860); in an enlarged form, Geschichte Jesu (2nd ed., 1891); and Handbuch der prot. Polemik gegen die röm.-kath. Kirche (1862; 7th ad., 1900; Eng. trans., 1906).

For his life see his Ideale und Irrtümer (1872; 5th ed., 1894) and Annalen meines Lebens (1891); and cf. generally Otto Pfleiderer, Development of Theology (1890); F Lichtenberger, Hist. of German Theology (1889).