Helene Demuth
Helene Lenchen Demuth was the housekeeper of Jenny and Karl Marx, later serving as the household manager and political confidante of Frederich Engels. She is best remembered as the mother of a child believed by most scholars to have been fathered by Marx.
Helene Demuth was born of peasant parents on December 31, 1820 in Sankt Wendel in todays Saarland. As a teenage girl she was adopted into the von Westphalen household, to work as a maid. In 1843 Karl Marx married Jenny von Westphalen. Helene Demuth joined their household in April 1845 in Brussels, where she was sent by Jennys mother. She stayed with the Marxes as a lifelong housekeeper, friend, and political confidante, and was commonly known to the family by the nicknames Lenchen or Nim.
Source: Wikipedia