Considered the father of Communism, Karl Marx reportedly had a side of his which has been kept well-hidden. As per an archived opinion piece on NYTimes by Ralph Buultjens, Marx has a secret which is not that well known. Marx had reportedly impregnated his family maid and then didn’t own up the child.

The portion of NYTimes article which mentions his illegitimate child which Marx abandoned is reproduced here in its entirety:

In 1851, while living in London, Marx fathered an illegitimate son by Helen Demuth, the longtime family maid. Fearing that this indiscretion would destroy his marriage and damage his public image, he organized an effective cover-up, whose participants were Marx’s friend and collaborator Friedrich Engels and Helen Demuth.

Engels pretended he was the father and Miss Demuth confirmed the deception. The infant, Fredrick Demuth, was given away to be brought up by a working-class family in London. The secret was preserved for more than four decades. In 1895, on his deathbed, Engels confessed to Eleanor Marx -one of Marx’s two surviving daughters. She was shattered by the revelation. Three years later, she committed suicide. In 1911, Marx’s other daughter, Laura, killed herself. Freddy Demuth grew up a neglected, lonely child. Marx could not afford any support. Engels, on whom Marx depended financially, sent small, infrequent remittances. Both Marx and Engels distanced themselves from Freddy. Marx never saw the boy. Freddy Demuth was poorly educated. For most of his life, he worked as a laborer and toolmaker. After Marx’s death, he established closer contact with his mother, who had then become Engels’s housekeeper. Freddy visited her weekly but was allowed only into the kitchen and servants’ rooms through the back door. Engels, like Marx, shunned him. After his mother’s death in 1890, Freddy hardly ever saw Engels. Neither Marx nor Engels provided a legacy for him. However, Marx’s daughters did give Freddy some money from their share of both estates. In 1929, after a hard, obscure life, Freddy died at 78 in a poor section of London. Nobody, not even his mother, told him the truth about his paternity and he died believing he was Engels’s bastard child. Marx’s secret was well-concealed. In his lifetime, only Helen and Engels shared in this confidence. On his death, they screened his papers to eliminate references to Freddy. Later, about the time Engels died, a few associates and family members came to know of the Demuth affair, but it was not much discussed. While researching this part of Marx’s life, a part that contains many clues to the development of his ideas, I became convinced that many Marxists had built a wall of silence around this secret. No major Soviet biographical material about Marx mentions Freddy. Other Marxists brush it off as irrelevant gossip. It is clear that to the Marxist world, Fredrick Demuth did not exist, or that the subject is taboo. The heroic proletarian image of the father of the revolution must not be tarnished by evidence of his duplicity, hypocrisy, frailty.