Goebbels, who aspired to be an author, obtained a Doctor of Philosophy degree from the University of Heidelberg in 1921. He joined the Nazi Party in 1924, and worked with Gregor Strasser in their northern branch. He was appointed Gauleiter (district leader) for Berlin in 1926, where he began to take an interest in the use of propaganda to promote the party and its programme. After the Nazi's seizure of power in 1933, Goebbels' Propaganda Ministry quickly gained and exerted control over the news media, arts, and information in Germany. He was particularly adept at using the relatively new media of radio and film for propaganda purposes. Topics for party propaganda included antisemitism, attacks on the Christian churches, and (after the start of the Second World War) attempting to shape morale.