New Testament scholar and theologian, professor successively at the universities of Göttingen and Giessen, and co-founder of the so-called Religionsgeschichtliche Schule (history of religions school) of biblical study. His many publications include works on New Testament textual criticism, Gnosticism, and the early church. His principal works were Die Religion des Judentums im neutestamentlichen (späthellenistischen) Zeitalter (1903; “The Religion of the Jews in the New Testament 【late Hellenistic】 Era”) and Kyrios Christos (1913; “Lord Christ”).