Eminent Protestant church historian and philologist; b. Kiel, Aug. 22, 1858; d. Munich, Feb. 13, 1940. After studying philology under H. Usener and U. Wilamowitz-Moellendorff, he taught at Rostock (1888), Giessen (1893), Strassburg (1897), Göttingen (1912), and Munich (1919–40). His chief interest was early Church history, to which he turned definitely in 1903 with his preparation of the edition of Eusebius's Histoire ecclesiastique for the Berlin Corpus (Die greichischen christlichen Schriftsteller der ersten drei Jahrhunderte, 3 v. 1903–09) and his plan for the edition of the Acta Conciliorum Oecumenicorum; he completed the volumes on the councils of ephesus (431) and chalcedon (451). In his preparation for these two monumental works he entered into an analysis of many of the perplexing historical problems of the first six centuries. His competence in dealing with the sources and institutions of Oriental tradition, chronology, geography, juridical concepts, and theology enabled him to publish numerous separate monographs shedding light on the growth of the Church from its Judeo-Christian beginnings to the Monophysite struggles. He composed monographs on the Easter Tables of the Early Church, the Pseudo-Apostolic Church Order, St. Athanasius, and on the schism and heresies of the fourth, fifth, and sixth centuries, always integrating the history of the Church with that of the Empire. His genius enabled him to make vivid the men and deeds of the past after the manner of the great maurists as an editor, and of Theodor Mommsen as an historian (Altendorf).
Bibliography: Gesammelte Schriften, ed. h. d. altendorf, 5v. (Berlin 1938–62). h. d. altendorf, Die Religion in Geschichte und Gegenwart, 7 v. (3rd ed. Tübingen 1957–65) 5:1589–90. w. otto, Historische Zeitschrift 162 (1940) 442–444.