On 1 April 1935 Arnold Sommerfeld, Heisenberg's teacher and doctoral advisor at the University of Munich, achieved emeritus status. However, Sommerfeld stayed on as his own temporary replacement during the selection process for his successor, which took until 1 December 1939. The process was lengthy due to academic and political differences between the Munich Faculty's selection and that of both the "Reichserziehungsministerium" (REM, Reich Education Ministry) and the supporters of "Deutsche Physik". In 1935, the Munich Faculty drew up a candidate list to replace Sommerfeld as ordinarius professor of theoretical physics and head of the Institute for Theoretical Physics at the University of Munich. There were three names on the list: Werner Heisenberg, who received the Nobel Prize in Physics in 1932, Peter Debye, who would receive the Nobel Prize in Chemistry in 1936, and Richard Beckerall former students of Sommerfeld. The Munich Faculty was firmly behind these candidates, with Heisenberg as their first choice. However, supporters of "Deutsche Physik" and elements in the REM had their own list of candidates and the battle commenced, dragging on for over four years.