Joseph Octave Delepierre (12 March 1802 – 18 August 1879) was a Belgian lawyer, archivist, diplomat, author and antiquary. He spent his later life in the United Kingdom, and is best known for his studies of macaronic language and literature.
Arthur John Brereton Marwick (29 February 1936 – 27 September 2006) was a British social historian, who served for many years as Professor of History at the Open University. His research interests lay primarily in the history of Britain in the twentieth century, and the relationship between war and social change. He is probably best known, however, for his more theoretical book The Nature of History (1970; revised editions 1981 and 1989), and its greatly reworked and expanded version The New Nature of History (2001). In the latter work he defended an empirical and source-based approach towards the writing of history, and argued against the turn towards postmodernism. He believed firmly that history was "of central importance to society".
Helene or Helena Demuth (30 December 1820 – 4 November 1890) was a German housekeeper who worked for Jenny and Karl Marx, and later served as the household manager and political confidante of Friedrich Engels.