 The "Religionsgeschichtliche Schule" ("history of religions school", 19th century) had a profound influence on the study of Gnosticism.The "Religionsgeschichtliche Schule" saw Gnosticism as a pre-Christian phenomenon, and Christian "gnosis" as only one, and even marginal instance of this phenomenon.According to Wilhelm Bousset (1865–1920), Gnosticism was a form of Iranian and Mesopotamian syncretism, and Eduard Norden (1868–1941) also proposed pre-Christian origins, while Richard August Reitzenstein (1861–1931), and Rudolf Bultmann (1884–1976) also situated the origins of Gnosticism in Persia.