https://en.wikipedia.org/wiki/Karl_Marx
Karl Marx was born on 5 May 1818 to Heinrich Marx and Henrietta Pressburg (1788–1863). He was born at 664 Brückergasse in Trier, a town then part of the Kingdom of Prussia’s Province of the Lower Rhine.[17] Marx was ancestrally Jewish; his maternal grandfather was a Dutch rabbi, while his paternal line had supplied Trier’s rabbis since 1723, a role taken by his grandfather Meier Halevi Marx.[18] Karl’s father, as a child known as Herschel, was the first in the line to receive a secular education; he became a lawyer and lived a relatively wealthy and middle-class existence, with his family owning a number of Moselle vineyards. Prior to his son’s birth, and to escape the constraints of anti-semitic legislation, Herschel converted from Judaism to Lutheranism, the main Protestant denomination in Germany and Prussia at the time, taking on the German forename of Heinrich over the Yiddish Herschel.[19]
Neither here nor there I suppose, but on the maternal side of my Austrian family, for whom, thanks to Adolf Hitler, I have documentation going back three generations beyond my grandmother, prior to which there were converts from Judaism to the Lutheran religion.
My grandmother just missed the wagons.
And when she died, I found my mother’s diary filled with quotations from Rosa Luxemburg.
Small world
If you convert from Judaism, you cease to be a Jew. If you start an atheist cult dedicated tothe cultural genocide of Jews, you are not a Jew. Marx was not a Jew after 5 and was an open antisemite.