Heidegger was originally destined for the priesthood, and a religious intensity characterizes all his writing. In his early work he regarded logic and mathematics as not so much resting on the psychological make-up of the human mind as taking on the medieval conception of a living faith. In 1919 Heidegger broke with Catholicism, so that his Being and Time can be seen as an attempt to demythologize theology. During the Nazi years Heidegger became an atheist, reading Nietzsche rather than Aristotle or Eckhart. Subsequently he turned to psychology and environmental issues, developing his own approach and terminology. But the earth that Heidegger sacralizes remained German. Heidegger was a nationalist, concerned with things German: landscape, peoples, their destiny, writers and philosophers.