He was born at Petershagen, near Minden, where his father, Georg Christof Friedrich, was preacher. In his tenth year he entered the orphanage at Halle, from which he duly passed to the university, his studies being interrupted in October 1813 by a period of military service, during which he was enrolled as a volunteer in a regiment of chasseurs. On the conclusion of peace he returned to Halle, and, having in 1817 taken his degree in philosophy, he became assistant head of the Minden gymnasium, and in 1818 was appointed director of the gymnasium at Cleves. Here he published his earliest work, a treatise which had considerable influence on subsequent investigations as to the origin of the gospels. In 1819 Gieseler was appointed a professor ordinarius in theology in the newly founded University of Bonn, where, besides lecturing on church history, he made important contributions to the literature of that subject in Ernst Friedrich Karl Rosenmüller's Repertorium, KF Stäudlin and HG Tschirner's Archiv, and in various university "programs." The first part of the first volume of his well-known Church History appeared in 1824. In 1831 he accepted a call to Göttingen as successor to GJ Planck. He lectured on church history, the history of dogma, and dogmatic theology. In 1837 he was appointed a Consistorialrath, and shortly afterwards was created a knight of the Royal Guelphic Order. The fifth volume of the Kirchengeschichte, embracing the period subsequent to 1814, and Dogmengeschichte, sometimes regarded as a sixth volume of the Church History, were published posthumously in 1855 by ER Redepenning, followed finally by the fourth in 1857. Less vivid and picturesque in style than Karl Hase, lacking August Neander's deep and sympathetic insight into the more spiritual forces by which church life is pervaded, he excels these and all other contemporaries in the fulness and accuracy of his information. His Lehrbuch der Kirchengeschichte, with its copious references to original authorities, is of great value to the student: "Gieseler wished that each age should speak for itself, since only by this means can the peculiarity of its ideas be fully appreciated.".
Works
Historisch-kritischer Versuch über die Entstehung und die frühesten Schicksale der schriftlichen Evangelien, Leipzig 1818
Ueber die Nazaräer und Ebioniten, in Archiv für alte und neue Kirchengeschichte vol. IV part II, Leipzig 1819
Etwas über den Reichstag zu Augsburg im Jahre 1530, Hamm 1821
Lehrbuch der Kirchengeschichte vol. I-III, Bonn 1824–35, vol. V, VI 1855, vol. IV 1857
