Karl August von Hase (25 August 1800 – 3 January 1890) was a German Protestant theologian and church historian.
He was born at Steinbach (near Penig) 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. He was the great-grandfather of Dietrich Bonhoeffer.
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 edition, 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 evangelische Glaubenslehre, für die gebildeten in der Gemeinde, (volume 1, 1827; volume 2, 1828; volume 3, 1829; second edition in two volumes, 1869 & 1870). But his reputation rests chiefly on his treatment of church history in his Kirchengeschichte, Lehrbuch zunächst für akademische Vorlesungen (1834, 12th edition, 1900; English translation, 1870).
His biographical studies, Franz von Assisi (1856; second edition, 1892), Caterina von Siena (1864; second edition, 1892), Neue Propheten (Die Jungfrau von Orleans, Savonarola, Thomas Münzer) are judicious and sympathetic. Other works are: