The field of secular theology, a subfield of liberal theology advocated by Anglican bishop John A. T. Robinson somewhat paradoxically combines secularism and theology. Recognized in the 1960s, it was influenced both by neo-orthodoxy, and the existentialism of Paul Tillich. Secular theology successfully digested modern movements like the Death of God Theology propagated by Thomas J. J. Altizer or the philosophical existentialism of Paul Tillich and eased the introduction of such ideas into the theological mainstream and made constructive evaluations, as well as contributions, to them.