The International Working Union of Socialist Parties (IWUSP; also known as 2½ International or the Vienna International;
German: Internationale Arbeitsgemeinschaft Sozialistischer Parteien, IASP) was a
political international for the co-operation of
socialist parties. IWUSP was founded on
February 27 1921 at a conference in
Vienna,
Austria by ten parties, including the
Independent Social Democratic Party of Germany (USPD), the
French Section of the Workers' International (SFIO), the
Independent Labour Party (ILP), the
Social Democratic Party of Switzerland (SPS), the
Social Democratic Party of Austria (SPÖ), and the
Federation of Romanian Socialist Parties (FPSR, successor to the
Socialist Party of Romania). In April 1921, it was joined by the
Spanish Socialist Workers' Party.
See more at Wikipedia.org...