Jonathan Miller examines the religious imagery that dominated the medieval mind and investigates the role that the emerging science of men like Copernicus, Vesalius and Galileo had upon Christianity. Such was the power of the church, however, that it was not until the late 18th century in France that confident modern atheism finally emerged. With the domination of Christianity from 500 C.E., he wonders how disbelief began to re-emerge in the 15th and 16th centuries. He discovers that division within the Church played a more powerful role than the scientific discoveries of the period. He also visits Paris, the home of the 18th century atheist, Baron D’Holbach, and shows how politically dangerous it was to undermine the religious faith of the masses.