In 180 AD, St. Irenaeus, the bishop of Lyon, France wrote Against Heresies. It is a collected work made up of 5 books, wherein Irenaeus examines the many schools of Gnostic thought of his day, in addition to various heretical Christian sects. He contrasts these with the orthodoxy of Christianity. This version of the work contains the last two books, which focus on refuting ancient heresies by referring to examples from the Old and New Testament. The...