The early church faced numerous heresies, including Gnosticism, which claimed special knowledge and secret truths. Irenaeus, a great early theologian, defended the importance of history and the Bible as the source of certainty. Montanism and Tertullian also emerged as movements against heresy, but their ideas sometimes went too far. Origen, a pioneering theologian, raised important questions and began a process of insight, but was wrong in many of his conclusions. [... more]