The Apologists were Christian writers of the second and third centuries who defended Christianity against the representatives of the Roman Empire, against Jewish teachers, and against groups that claimed to be Christian but were adjudged to be heretical by the emerging 'catholic' church. Obviously, their works were affected by the situations in which they were written however, their essential continuity with the views found in the Apostolic Fathers on matters pertaining to the law and ethics is clear. Irenaeus, Bishop of Lyon, was a defender of Christian orthodoxy against two sets of teachings, among others those of Marcion and of the Gnostics. This he did in his major work Against Heresies. Marcion took to an extreme what he found in the writings of Paul, and rejected the Old Testament and its law so completely that the church founded by him recognized as scripture only the Gospel of Luke and seven letters of Paul.