The term "revisionism" has been used in a number of contexts to refer to different revisions (or claimed revisions) of Marxist theory. Those who opposed Karl Marx's revolution through his lens of a violent uprising and sought out more peaceful, electoral means for a socialist revolution are known as revisionists. Eduard Bernstein, a close acquaintance of Marx and Engels, was one of the first major revisionists, and was prominent in the Social Democratic Party of Germany (SPD).[3]