nor the Evangelical Church... as institutions, felt it possible to take up an attitude of open opposition to the regime". Catholic resistance In the 1920s and 1930s, the main Christian opposition to Nazism had come from the Catholic Church. German bishops were hostile to the emerging movement and energetically denounced its "false doctrines". A threatening, though initially mainly sporadic persecution of the Catholic Church in Germany followed the Nazi takeover. Hitler moved quickly to eliminate Political Catholicism, rounding up members of the Catholic political parties and banning their existence in July 1933. Vice Chancellor Franz von Papen, the leader of the Catholic right-wing, meanwhile negotiated a Reich concordat with the Holy See, which prohibited clergy from participating in politics. Catholic resistance initially diminished after the Concordat, with Cardinal Bertram of Breslau, the chairman of the German Conference of Bishops, developing an ineffectual protest system. Firmer resistance by Catholic leaders gradually reasserted itself by the individual actions of leading churchmen like Josef Frings, Konrad von Preysing, Clemens August Graf von Galen and Michael von Faulhaber. Most Catholic opposition to the regime came from the Catholic left-wing in the Christian trade unions, such as by the union leaders Jakob Kaiser and Nikolaus Gross. Hoffmann writes that, from the beginning: In the year following Hitler's "seizure of power", old political players looked for means to overthrow the new government. The former Catholic Centre Party leader and Reich Chancellor Heinrich Brüning looked for a way to oust Hitler. Erich Klausener, an influential civil servant and president of Berlin's Catholic Action group organised Catholic conventions in Berlin in 1933, and 1934 and spoke against political oppression to a crowd of 60,000 at the 1934 rally. Deputy Reich Chancellor von Papen, a conservative Catholic nobleman, delivered an indictment of the Nazi government in his Marburg speech of 17 June. His speech writer Edgar Jung, a Catholic Action worker, seized the opportunity to reassert the Christian foundation of the state, pleaded for religious freedom, and rejected totalitarian aspirations in the field of religion, hoping to spur a rising, centred on Hindenburg, Papen and the army. Hitler decided to strike at his chief political opponents in the Night of the Long Knives. The purge lasted two days over 30 June and 1 July 1934. Leading rivals of Hitler were killed. High-profile Catholic resistors were targeted—Klausener and Jung were murdered. Adalbert Probst, the national director of the Catholic Youth