Moneta became active in the peace movement in 1870. In 1878 he helped establish the League of Liberty, Brotherhood and Peace in Milan. In 1887 he helped to found the Society for International Peace and Justice, and the Lombard Union for International Peace and Understanding, of which he became president. Moneta regularly attended international peace congresses, and from 1895 onwards he was a member of the Permanent Interntional Peace Bureau. He actively worked to establish better understanding between countries on the verge of conflict, especially through arbitration. He was also editor of the journal "La Vita Internazionale".
Pratt was one of the founders of the Permanent International Peace Bureau and member of its commission until 1904. He founded and presided over the International Arbitration and Peace Association.
Bajer promoted Nordic neutrality and brotherhood. He was one of the initiators and founders of the Permanent International Peace Bureau, and he was the first president of the Peace Bureau. Bajer was also member of the council of the Inter-Parliamentary Union. He organized peace work both in Denmark and internationally, both popular peace movements and parliamentary peace work. Bajer was Scandinavia's most prominent peace advocate.