Gustaf Aulén (1879-1978) was the Bishop of Strängnäs in the Church of Sweden and the author of Christus Victor: An Historical Study of the Three Main Types of the Idea of Atonement in 1931. This classic work analyzes the doctrine of the atonement of Jesus, suggesting that the three main interpretations in Christian history are the Christus Victor theory, the Satisfaction theory, and the Moral Influence theory. Aulén is also known in the Swedish Lutheran Church as a composer of widely used church music. Aulen also authored The Faith of the Christian Church and Reformation And Catholicity.