an active oppositionist. Talk of a coup again began to circulate, and for the first time the idea of killing Hitler with a bomb was taken up by the more determined members of the resistance circles, such as Oster and Erich Kordt, who declared himself willing to do the deed. At the army headquarters at Zossen, south of Berlin, a group of officers called Action Group Zossen was also planning a coup. When in November 1939 it seemed that Hitler was about to order an immediate attack in the west, the conspirators persuaded General Wilhelm Ritter von Leeb, commander of Army Group C on the Belgian border, to support a planned coup if Hitler gave such an order. At the same time Oster warned the Dutch and the Belgians that Hitler was about to attack them—his warnings were not believed. But when Hitler postponed the attack until 1940, the conspiracy again lost momentum, and Halder formed the view that the German people would not accept a coup. Again, the chance was lost. With Poland overrun but France and the Low Countries yet to be attacked, the German Resistance sought the Pope's assistance in preparations for a coup to oust Hitler. In the winter of 1939/40, the Bavarian lawyer and reserve 'Abwehr' officer Josef Müller, acting as an emissary for the military opposition centered around General Franz Halder, contacted Monsignore Ludwig Kaas, the exiled leader of the German Catholic Zentrum party, in Rome, hoping to use the Pope as an intermediary to contact the British. Kaas put Müller in contact with Father Robert Leiber, who personally asked the Pope to relay the information about the German resistance to the British. The Vatican considered Müller to be a representative of Colonel-General von Beck and agreed to offer the machinery for mediation. Oster, Wilhelm Canaris and Hans von Dohnányi, backed by Beck, told Müller to ask Pius to ascertain whether the British would enter negotiations with the German opposition which wanted to overthrow Hitler. The British agreed to negotiate, provided the Vatican could vouch for the opposition's representative. Pius, communicating with Britain's Francis d'Arcy Osborne, channelled communications back and forth in secrecy. The Vatican agreed to send a letter outlining the bases for peace with England and the participation of the Pope was used to try to persuade senior German Generals Halder and Brauchitsch to act against Hitler. Negotiations were tense, with a