The Mission and Expansion of Christianity in the First Three Centuries

Carl Gustav Adolf von Harnack (7 May 1851 – 10 June 1930) was a German Lutheran theologian and prominent church historian. He produced many religious publications from 1873 to 1912. Harnack traced the influence of Hellenistic philosophy on early Christian writing and called on Christians to question the authenticity of doctrines that arose in the early Christian church. He rejected the historicity of the gospel of John in favor of the synoptic gospels, criticized the Apostles' Creed, and promoted the Social Gospel.