In 1914, when World War I broke out, Zeth Höglund together with Ture Nerman represented the Swedish-Norwegian members of the Zimmerwald Conference, the international socialist anti-war movement which gathered in the small Swiss village of Zimmerwald. There the young Swedish socialist met Vladimir Lenin, Grigory Zinoviev, Vatslav Vorovsky, Karl Radek and Leon Trotsky: Zeth Höglund and Ture Nerman felt very close to the Russian Bolsheviks.