The work of theologians as members of parliament for various political parties in Germany showcases an important interlinking of religion and politics since the Frankfurt Parliament. Nevertheless their role and work remained largely unexplored in regard to the Protestant Church. By assessing the parliamentary work of Protestant theologians since 1848, the project aims to analyse the reciprocal effects of their political actions and theological rationale. The research focuses on to what extend the political participation of Protestant theologians in democratic structures promoted the successive approval of political pluralism throughout the times of nationalistic and monarchy-supporting Protestantism in Germany. An initial study explores the activities of three theologians as members of parliament: Rudolf Otto (1913-1918 member of the Prussian House of Representatives [National Liberal Party]; 1919 member of the Prussian Constituent Assembly [German Democratic Party]), Magdalene von Tiling (1921-1930 member of the Landtag of Prussia; 1930-1933 member of the German Reichstag [German National People's Party]) and Heinrich Albertz (1947-1955 member of the Landtag of Lower Saxony; 1963-1970 member of the Berlin House of Representatives [Social Democratic Party]; high offices in Lower Saxony and West Berlin; member of the party's policy committee). Each of these theologians represents a different stage in the history of German democracy. Their party-political orientation is characteristic for their respective era. By analysing the political and parliament work of these three theologians the initial study aims to identify developments of their party-political orientation, their responsibilities within the party, their theological bias, and the degree of acceptance amongst the Church.