The historical investigation of the origins of Christianity began with the English deists, who, being philosophers and not professional historians, were for that very reason able to give the first forward impulse to the historical study of Jesus and of primitive Christianity. No purely historical interest could have induced Christian Europe to apply criticism to its sacred books, the facts of salvation, and the divine person of the Saviour. A new and philosophic conception of religion was required, directly opposed to the older view, if any serious effort was to be made to find in the writings of the New Testament and in the earliest Christian history the evidence for critically tested historical statements, and if these writings were to be read and the history studied from any other point of view than that of traditional dogmatism, Protestant or Catholic.