The murder of nine African Americans at the Emanuel African Methodist Episcopal Church in Charleston in 2015 and the murder of 11 Jews at the Tree of Life synagogue three years later in Pittsburgh were no doubt similar events.

However, the ancient racial hatreds which provoked them — the racial hate and murder of Jews and the racial hatred, murder and enslavement of Africans, which together add up to the main objects of western racism — have usually been considered profoundly different.

Scholars who have devoted themselves to the field of antisemitism have rarely engaged in the field of anti-Black racism and vice versa.

In Towards the Final Solution (1979), George Lachmann Mosse, the great American Jewish historian, noted that these two racisms existed in separate geographical spheres. In the 18th and 19th centuries, in Great Britain, with its great overseas empire, there was a good deal of hatred of Blacks, and little hatred of Jews, about whom little was known. In parts of Europe such as Germany, the Hapsburg Empire or Russia, where Black people were relatively unknown, Jews were hated, and no-one bothered too much about Blacks.

One of the greatest writers on antissemitism, the French historian Léon Poliakov, considered that the European hatreds of Jews and Blacks occupied entirely different psychological spheres, had little if anything in common, and were expressed by completely different people and for completely different reasons.

Similarly, in our own troubled times, Jeremy Corbyn apparently feels strongly that anti-Black racism is a terrible thing, but does not appear to conceive of antisemitism as being anything much to do with genuine racism. His understanding of racism appears to be mainly defined by ideas about power and colour and his attitude towards Jews and Israel appear to frame them in a world of privilege and whiteness. Racism and antisemitism seem to occupy different spheres of his brain. I hope he reads my new book. But I don’t think he will.

What I am arguing in this new work (Hybrid Hate: Conflations of Anti-Black Racism and Anti-Semitism from the Renaissance to the Third Reich. New York: Oxford University Press, 2020) is that in fact anti-Black racism and antisemitism are not merely similar but have been in constant communication, overlap and exchange with each other for centuries. In medieval Europe and in the early modern period the demonisation of Jews and Blacks ran in parallel. For thinkers of the Renaissance, Jews and Blacks were considered outside the usual human framework and the idea began to spread that Jews and Blacks had origins and founder events that were quite separate from the rest of humanity. Not everyone, it was argued, descended from Adam and Eve. By the 1820’s even Goethe had no hesitation in proclaiming that Jews and Blacks had different founding events from Europeans. There were many other similarities in the way Blacks and Jews were imagined but mostly what they had in common was their position as radical outsiders.

Then something odd happened. In 1777 a slave from the west coast of Africa recounted to a German missionary on a Caribbean island that in the kingdom of Loango, his home country, there were black Jews. They kept the Sabbath, he explained, did not eat with the local “Negroes” and had images of snakes and lizards on their tombstones.

The theorists and scientists of the time leaped upon this seemingly incredible story: the discovery of the existence of these remarkable black Jews suggested many fundamental things about the nature of race, including that Jews could come in many different colours, including pitch black.

As the years passed travellers kept finding new black Jewish communities in different parts of the world to support this notion: in Waregla in the Sahara (where an English traveller found Jews “deeply stained with negro blood”) in Timbuktu, the Jordan Valley, Bombay, Cochin and Ethiopia.

This played into a growing conviction on the part of race scientists that Jews and Blacks had the same origins – that black blood flowed in the veins of Jews and that the skin of supposedly white Jews was actually black, even if it kind of looked white.

I should also note that as Jews were being constructed as Blacks, Blacks were also being constructed as Jews and, throughout the period covered by this book dark, coloured people throughout the world were systematically being imagined as Jews. In Africa alone the Masai, Yoruba, Igbo, Tutsi, Zulu, Xhosa, Bassa, Ibibio, Fula, Banyankole, Baluba, Khoikhoi, Shona, Makalanga, Esan, Efik, Baluba, Fon, Fulani, Meru, Nga, Soninke, Tiv and Yibir, among others, were regularly constructed, racialized, explained, perceived and described, precisely as Jews, as people with biological, Jewish roots in whose lives, ideas and practices remnants of an ancient Judaism could still allegedly be made out and in whose languages traces of Hebrew could still allegedly be identified.

Skin tone was a minutely studied subject in the 19th century. One of the greatest authorities on pigmentation was the Englishman John Beddoe. He had served with distinction in the Crimean War in the British field hospital made famous by Florence Nightingale, and while he was there did a physical anthropological study of the skins of the multi-national population incarcerated in the hospitals of the Dardanelles.

He went on to analyse the eye and hair colors of the peoples of Europe and thereby laid the foundation of the great pigmentation surveys, which would be carried out in Germany and elsewhere in Europe. One of his achievements was to create a meticulously annotated “index of nigrescence” of the population of Great Britain. Jews scored fully one 100 per cent on his nigrescence index.

One of the largest pigmentation studies, which involved nearly seven million schoolchildren, was carried out in Germany shortly after German unification in 1871 by the distinguished German scientist Rudolf Virchow. The teachers were provided with a set of instructions which required the children to stand in line with the blondest haired children at one end and the darkest haired at the other, in a continuum of hair colour. This way the children learned that there was a hierarchy of colour.

Skin colour was shown in the study to be a function not only of what was visible, but also of the relationship between hair and eye colour. Visible skin colour was in fact of no importance. Children were asked to roll up their sleeves to reveal the colour of their arm, beneath their clothes, which would be unaffected by the effect of the sun. In other words, the skin color that you perceived with your naked eye, was not necessarily the real skin colour of the individual (for that you would have to partially undress him/her) and there were “scientific” ways of determining what skin colour actually was.

This was precisely the point at which the hatred of Jews was being increasingly expressed in racial terms. Wilhelm Marr was the German racist who in 1879 introduced the term antisemitism into the political lexicon of the world and who is known as the father of modern antisemitism.

Marr started his political life as an anarchist. He had no particularly anti-Jewish views and in fact had three Jewish wives, one of whom he loved to distraction. It was during an extended trip to north America that he learned how to be a racist. He’d seen Black slavery in action and wholeheartedly approved of it. He loathed Black people. His contempt for Blacks was soon transferred wholesale to Jews. What the Americans did to Blacks, Europeans should now do to Europe’s Blacks — the Jews.

Filled with the views of the racist thinkers of the time such as the embittered Scots physician Robert Knox or Joseph Arthur Gobineau, the French aristocrat who helped develop the theory of the Aryan master race, Marr argued that the blood of the despised Negro flowed freely in the veins of Jews. Jews really were somatically as well as metaphorically the Blacks of Europe.

Over the next few decades the ancient streams of anti-Jewish hatred on the one hand and the hatred of Blacks on the other joined together in a mighty torrent. Even before the rise of Nazism the equation of Jews and Blacks started to fill the media of the time. Theodor Fritsch, the well-known German publisher of the antisemitic magazine Hammer stressed the sexual danger of Blacks and Jews. He explained that Jews’ unfortunate characteristics could best be explained by their African ancestry.

The acclaimed French novelist and Holocaust denier, Louis-Ferdinand Céline, went even further: he considered Jews to be entirely African: “Le Juif est un nègre – la race sémite n’existe pas” (the Jew is a Negro – the Semitic race does not exist). Nazi and Fascist race theorists embraced these ideas enthusiastically. There was a broad consensus among Nazi and Italian Fascist physical anthropologists that Black people were utterly inferior and there were marked Negroid elements in Jews. These ideas were as present in the United States as they were in Europe. The Ku Klux Klan regularly lumped Blacks and Jews together. In 1910, Dr Arthur Talmage Abernethy — a well-educated man, and author of some fifty books, authored The Jew a Negro. Abernethy argued that “the Jew of today, as well as his ancestors in other times is the kinsman and descendant of the Negro”.

From a Nazi point of view Blacks luckily were visible and needed no other signifier. Jews were not always visibly ‘Negroid’, but they invariably did have internal, invisible, ‘Negro’ blood and their skin colour was often illusory. Jews also had other somatic Negroid chactaeristics. Nazis were convinced of the need to rid Germany both of ‘Negroid Jews’, and ‘Negroes’ themselves.

As is well known, much of the inspiration for the discriminatory legal codes enacted against Jews, Blacks and others by the Nazis came from the United States which discriminated so cruelly against its African American population. The main problem with overall American racial legislation, however, from a Nazi perspective, was that officially the Americans did not include Jews in the category of “coloureds”.

But in 1934 Roland Freisler, later the presiding judge of the Nazi Volksgerichtshof (People’s Court) observed that actually the American legislation could be used without much modification because “any judge would reckon the Jews among the coloureds, even though they look outwardly white”.

As illogical, frenzied and neurotic streams of Judeophobia and Negrophobia clashed or ran together or in parallel to create this race madness it emerged that Blacks and Jews, as an indivisible entity, presented the greatest threat to white, Aryan civilization not only in Germany but throughout the world. Hitler argued that Germany was threatened by Blacks and had been deliberately ‘negrified’ by the Jews whose intent was to weaken and destroy German society through racial contamination. In Mein Kampf he wrote of the Jews: “Systematically these Negroid parasites in our national body corrupt our innocent fair-haired girls and thus destroy something that can no longer be replaced in the world”.

On a visit to the Auschwitz concentration camp, I was struck by the sophisticated, modern facilities which had been available for the daily ablutions of the SS and other German personnel, and by the total absence of such facilities, or of soap, or of clean water, for Jews.

Jews, barely able to wash, were rendered black and filthy in comparison to their persecutors. The contrasting visions in Der Stürmer and elsewhere of black or dark Jews and spotless white Aryans had been made real.

Tudor Parfitt is author of ‘Hybrid Hate: Conflations of Anti-Black Racism and Anti-Semitism from the Renaissance to the Third Reich’ (New York: Oxford University Press, 2020)