Karl Marx, the progenitor of the most well-known strain of socialist theory in the last century, was born in the city of Trier in 1818 to a married Lutheran couple, both of whom had converted from Judaism before their son was conceived. Karl's father, Heinrich Marx, was descended from a distinguished line that was at the center of German Judaism all the way back to the fourteenth century, where one "Eliesar" was the rabbi for the Mainz community (the core of medieval Talmudic study). Both of Karl Marx's grandfathers were rabbis, and his uncle was the latest in a line of rabbis for Trier that stretched back to 1650. Members of Marx's family had been present for all the horrific events in the persecution of the Jews up to that point, including the 1418 expulsion of the Jews from Trier. "The family tree is itself the Book of Lamentations," James Carroll writes in his Constantine's Sword: The Church and the Jews. "Open it to any verse, and it will weep." Heinrich Marx was born as Herschel Levi, but changed his name and converted to Lutheran Christianity in his adulthood, possibly in response to the post-Napoleonic backlash against the Jewish Emancipation in Europe. Martin Luther was not known for his love of Judaism, nor could this be seen as anything but a central and integral part of his theological views. The Lutheran tradition in Germany was in no way particularly friendly to Jews - but it was the state religion, and considered far more "enlightened" than membership in the "archaic" Roman Catholic Church.
Karl Marx's mother was also a Lutheran convert from Judaism, and so when Adolf Hitler would refer in much later years to "that Jew Marx", he would be technically correct. Karl Marx, the son of a Protestant lawyer, was also a Jew, and one very aware of his family's history and rich heritage. And yet, Marx's true heritage was that of the Enlightenment and the previous century, particularly that of Voltaire, a prolific writer who denounced the decadence of the Crown and the Church, promoted modernity, democracy, and pluralism - and was also the first "modern" anti-Semite. Voltaire's disdain for the Jews issued largely from his admiration of his inspiration Cicero's own anti-Judaism, and allowed him to simultaneously denounce the horrific persecution of the Jews in the history of the Roman Catholic Church and to write in 1771 that the Jews "are, all of them. . .born with raging fanaticism in their hearts, just as the Bretons and Germans are born with blond hair. I would not be in the least surprised if these people would not some day become deadly to the human race." Marx knew that his father had indirectly agreed by shrugging off the legacy of his family and their traditional religion like an old cloak, as something outdated and unattractive that impeded his progress to becoming a successful lawyer and a model, and modern, citizen. The influence that this had on Heinrich Marx's son is not known, but Karl Marx would soon more avidly and directly voice his own disdain for Jews, largely in the terms brought by a dual legacy of Lutheran upbringing and study of Voltaire's own "Enlightenment" as to the role of Judaism in history.
Karl Marx was educated in both Bonn and Berlin, where he became heavily interested in and influenced by G.W.F. Hegel and Ludwig Feuerbach, falling in with the "Young Hegelians" who sought to use historical dialectic to understand the modern Europe that was still being created before their very eyes. Marx, upon returning to Trier in 1842, began to submit his own philosophical and historical articles to a Cologne newspaper, Rheinishe Zeitung, that showed the influence of his education. In 1843, Karl Marx's first essay of note was produced: "On The Question of the Jews". Feuerbach was notorious for his claim that the biblical and rabbinic YHWH was "nothing but the personified selfishness of the Israelitish people". But Marx would outshine his mentor in his virulence: "Money," he wrote, "is the jealous god of Israel, beside which no other god may exist." Marx was already distancing himself from his Christian upbringing, but his words were "barely more than a glib rehash of the twisted charges of Christian preachers" (Carroll). Marx reiterated a stereotype of Jews as capitalist puppeteers that was still in its earliest stages: "The chimerical nationality of the Jew is the nationality of the trader, and, above all of the financier." Marx hoped to uncover what he called "the real Jew":
Let us not seek the secret of the Jew in his religion, but let us seek the secret of the religion in the real Jew. What is the profane basis of Judaism? Practical need, self-interest. What is the worldly cult of the Jew? Huckstering. What is his worldly god? Money.
Very well: then in emancipating itself from huckstering and money, and thus from real and practical Judaism, our age would emancipate itself.
An organization of society which would abolish the preconditions and thus the very possibility of huckstering, would make the Jew impossible. His religious consciousness would evaporate like some insipid vapour in the real, life-giving air of society . . .
We discern in Judaism, therefore, a universal antisocial element of the present time, whose historical development, zealously aided in its harmful aspects by the Jews, has now attained its culminating point, a point at which it must necessarily begin to disintegrate.
In the final analysis, the emancipation of the Jews is the emancipation of mankind from Judaism.
Less than five years after this essay's publication, Marx and his compatriot Friedrich Engels would publish The Communist Manifesto, whose target would not be the Jews but heartless capitalists, regardless of nationality, race, or religion. Yet, the earlier screed in the Cologne paper would be a part of the new legacy of racial anti-Semitism, which was eclipsing the largely religious anti-Judaism of traditional Christian Europe. Jews would acquire a dual role of villain in the eyes of modern European society: a "vulgar" stereotype, held by peasants and the poor, of the Jew as a greedy, heartless financier who secretly pulled the strings of the world (based in fear of the up-and-coming capitalist class, whose ranks were mostly white and Christian, but where names like Sassoon and Oppenheim stuck out to already-xenophobic minds); and, conversely, the murky fear held by middle-and-upper-class Europeans of the new breed of radicals, socialists, anarchists, Marxists, all of whom demanded a revolution against the unjust and uncaring brutality of capitalism.
The salient effects of this legacy would become tragically clear in the twentieth century and the political upheavals that accompanied it in Leninism and fascism. That Marx was a Jew would become a well-guarded secret in the Soviet Union, where his family tree and history was suppressed by the Kremlin, whose officers continued to foster the anti-Semitic rage among citizens of Russia and the other Soviet republics as part of their own grasp for power. Many was the self-proclaimed Marxist who echoed Marx's own anti-Semitic statements and applied them to class struggle, identifying the Jew with the wealthy and fascist - while the wealthy and fascist sectors of society used Marx's heritage to identify the Jew with the dangerous revolutionary. National Socialism would take full advantage of these seemingly contradictory strands of xenophobia: Joseph Goebbels would make effective use of propaganda machines to convince the economically depressed of Germany that then-powerful, Weimar Republic-backed German capitalists were the outgrowth of a Jewish conspiracy to oppress the white working class, while simultaneously playing on the fears of middle-class Germans by describing Marxist socialism and its popular parties in Germany as simply another facet of that same conspiracy. Marx was derided as a Jew by the Nazis; his ideas on the Jews were echoed, however, in their next breath. The Protocols of the Meetings of the Learned Elders of Zion, and their promoters such as Father Charles Coughlin, claimed to explain the religion of the Jews, just as Marx did, in terms of a Jewish worship of money above all else and a corresponding manipulation of society towards exclusively monetary ends; this "materialism" was also seen as the source of a dangerous moral relativism and the rising "scourge" Communism, in the form of an ascendant Soviet Russia. (Carroll points out how deep the fear of Communism went into the souls of Europe: no Nazi was ever excommunicated from the Catholic Church for membership in the party, but four years after World War II, Pope Pius XII summarily struck all Communist members from the rolls of the Holy See.) Even the Zionist Theodore Herzl based his philosophy, in part, upon a view that blurred the line between Jewish self-criticism and Marx's Jewish self-hatred: that Jews, by living as outcasts in a Gentile-controlled world, had created a "crooked morality" that reduced their culture to buying and selling, pure "huckstering", as Marx put it. The contradictory nature of Marx's anti-Semitism exemplified the fear of the Jews in the century to come - one more form of unintended prescience in how Marx viewed the world.
In response to the writeup below, I agree with Carroll's contention that anti-Judaism became racialized antisemitism during the Spanish Inquisition. Anti-Judaic and racial ideologies were inseparable by the time Marx began to write. The contention of a damaging Jewish ideology corrupting Europe was already identified with 'hidden' Jews integrated into society through bloodlines; Jewish perfidy was also considered by hostile intellectuals to be a racial trait. Voltaire's writing remains some of the most stomach-turning evidence of this.