 A crucial event in his political development was his participation, a few weeks after Ferdinand Lassalle’s death, in the second Congress of the German Workers’ Association, Vereinstag deutscher Arbeitervereine (VDAV) in Leipzig in October 1864. The VDAV was founded initially as a counterweight to Lassalle’s more radical, more Prussian, Allgemeine Deutsche Arbeiterverein (ADAV) (General German Workers’ Association)—one of the ancestors of the current Social Democratic Party. The VDAV was set up as a loose organization, in contrast again to the ADAV, but acquired more structure later as the Federation of German Workers’ Associations, Verband Deutscher Arbeitervereine (which kept the same initials in German) (SED 1966, 216; Na’aman 1980). Lange attended the 1864 Congress as a representative of his Duisburg consumers’ cooperative. He was elected to the Standing Committee and attempted to mediate between various factions, in particular between the Lassalleans of the ADAV and the more liberal participants of the Congress. The politics were quite complicated, since there were voices even further to the left of the leadership of the ADAV, famously Marx and Engels. The disagreements were in essence about which existing social, political, and economic structures and forces should or had to be accepted and worked within, and which could and should be replaced. The disagreements reflected splits between the middle class and the working class. Despite his role as mediator, Lange was clear that the workers must not be co-opted for a bourgeois, liberal agenda, and that the workers’ movement as a whole must remain focused on the class interests of the working class (Bernstein 1892, 139; Mehring 1908, 368). Lange failed to succeed in his mediating efforts, and felt compelled to explain his own position in his Arbeiterfrage (The Labor Question) (Lange 1865a).