The International Institute of Social History (IISG) is one of the largest archives for labour, left and social history in the world. It is an independent scientific institute in Amsterdam (the Netherlands). the IISG is part of the Royal Netherlands Academy of Arts and Sciences. It was founded in 1935 by Nicolaas Posthumus. The large archives of the institute (ca. 50 km) harbour invaluable and extensive papers of several international social movements and currents, including the papers of Rosa Luxemburg, Friedrich Engels, Karl Marx and Mikhail Bakunin.
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