moved his office to Berlin, the cooperation between Pacelli and Kaas became even closer. Out of this involvement grew a formal but close and lasting friendship, which remained one of the basic factors throughout Kaas's life. In this position Kaas contributed to the successful conclusion of the Prussian Concordat negotiations with Prussia in 1929. After this achievement, Pacelli was called back to the Vatican to be appointed Cardinal Secretary of State. Pacelli asked Kaas, who had accompanied him on his travel, to stay in Rome but Kaas declined because of his ecclesiastical and political duties in Germany. Nonetheless, Kaas would frequently travel to Rome, where he would stay with Pacelli, and experience first hand the conclusion of the Lateran Treaty, which he penned an article on. In 1931 and 1932 continued as an advisor in negotiations for a Reichskonkordat; that, however, came to nothing. In 1929, Kaas published a volume of Nuncio Pacelli's speeches. In the introduction, he described him as: “Angelus not nuntius, ... his impressive personality, his sacerdotal words, the popularity he generated in public meetings" Kaas as party chairman Without being a candidate, September 1928 Kaas was elected chairman of the Centre Party, in order to mediate the tension between the party's wings and to strengthen their ties with the Bishops. Under Kaas' watch, the centre began drifting steadily rightward. Much of his time was occupied in arranging a Reich-wide Concordat. This work made him increasingly distrustful of democracy, and he eventually concluded that only authoritarian rule could protect the interests of the church. From 1930 onwards, Kaas loyally supported the administration under the centre's Heinrich Brüning, who served as the leader of the party's Reichstag faction due to Kaas' frequent travel to the Vatican. In 1932 he campaigned for the re-election of President Paul von Hindenburg, calling him a "venerated historical personality" and "the keeper of the constitution". As his frequent Vatican travels hampered his work as chairman, Kaas was prepared to yield the leadership of the party to Brüning, whom Hindenburg had dismissed in May, but the former Chancellor declined and asked the prelate to stay. In 1932 Kaas and Brüning led the Centre Party into opposition to the new Chancellor: party renegade Franz von Papen. Kaas called him the "Ephialtes of the Centre Party". Kaas tried to re-establish a working parliament by cooperation with the National Socialists. Hitler's Enabling Act Kaas felt betrayed when