Right wing and nationalist armed groups, like the nationalist "Der Stahlhelm" or the nazi "Sturmabteilung", as well as the left-wing "Roter Frontkämpferbund" had continued to radicalize and intensify the political struggle in Germany. The Reichsbanner was initially formed in reaction to the far right's "Beer Hall" Putsch and far left's Hamburg rebellion, both failed coups, which had taken place at the end of 1923. On 22 February 1924 members of the SPD, the German Centre Party, the German Democratic Party and trade unionists in Magdeburg established the "Reichsbanner". However the proportion of Social Democrats in the membership clearly outweighed all others, with estimates of up to 90 per cent. In the fall of 1927 the "Reichsbanner" expelled all members belonging to the Old Social Democratic Party, accusing the party of seeking alliances with fascists.