Martin Heidegger was a philosopher most known for his contributions to German phenomenological and existential thought. Heidegger was born in rural Messkirch in 1889 to Catholic parents. While studying philosophy and mathematics at Albert-Ludwig University in Freiburg, Heidegger became the assistant for philosopher Edmund Husserl. Influenced by Husserl, Kierkegaard, and Nietzsche, Heidegger wrote extensively on the quality of Being, including his opus Being and Time. He served as professor of philosophy at Albert-Ludwig University and taught there during the war. In 1933, Heidegger joined the National Socialist German Worker's (or Nazi) Party and expressed his support for Hitler in several articles and speeches. After the war, his support for the Nazi party came under attack, and he was tried as a sympathizer. He was able to return to Albert-Ludwig University, however, and taught there until he retired. Heidegger continued to lecture and write until his death 1973.