In the 1920s, Benito Mussolini had started to subsidise the right-wing Heimwehr (Home Defense) movement in Austria, and after Chancellor Engelbert Dollfuss had seized dictatorial power in March 1933, Austria had fallen within the Italian sphere of influence. The terrorist campaign mounted by Austrian Nazis, with the open support of Germany, against the ultraconservative Dollfuss regime had the aim of overthrowing him to achieve the Anschluss, which caused considerable tensions between Rome and Berlin. Mussolini had warned Hitler several times that Austria was within the Italian, not German, sphere of influence and that the Germans had to cease trying to overthrow his protégé, Dollfuss. On 25 July 1934, the July Putsch in Vienna had seen Dollfuss assassinated by the Austrian SS and an announcement by the Austrian Nazis that the Anschluss was at hand. The Austrian Nazis attempted to seize power all over Austria, and the SS Austrian Legion, based in Bavaria, began to attack frontier posts along the German-Austrian border in what looked like the beginning of an invasion. In response, Mussolini had mobilised the Italian Army, concentrated several divisions at the Brenner Pass and warned Hitler that Italy would go to war with Germany if he tried to follow up the putsch by invading Austria. The Austrian-born Hitler, although deeply offended by Mussolini's blunt assertions that his birthplace was within the sphere of influence of any power other than Germany, realised he was in no position to do anything except to beat a humiliating retreat. To his disgust, he had to disallow the Putsch that he had ordered and could not follow it up by invading Austria, whose government crushed the Putsch by the Austrian Nazis.