In 1879 and 1880, Heinrich von Treitschke, an influential German nationalist historian, published a series of articles that drew attention to a fateful phrase: "Die Juden sind unser Unglück" ("The Jews are our misfortune"). Eventually, that slogan would be written on banners at Nazi Party rallies. Just before Treitschke's essay appeared, another German writer, anti-Jewish journalist Wilhelm Marr, coined the term antisemitism. But what that term denotes--discrimination and hatred against Jews--is arguably the world's longest hatred.

In the year 70 c.e., the Romans under Titus starved and/or slaughtered at least 600,000 Jews at Jerusalem. Early-day Christian theologians said the Jews brought the massacre upon themselves because they had rejected Jesus as their Messiah. Violence subsequently raged against Jews for centuries. Jews were expelled from England in 1290, from France in 1306, and from Spain in 1492.

As religious toleration and civil rights developed in 18th- and 19th-century Europe, Jews became almost equal citizens under the law. Those liberal trends, however, did not eliminate hate for Jews. In the late 1800s, for instance, anti-Jewish pogroms broke out in Russia and Poland, killing thousands.

Over the centuries antisemitism has taken different but related forms: religious, political, economic, social, and racial. Jews have been discriminated against, hated, and killed because prejudiced non-Jews believed Jews belonged to the wrong religion, lacked citizenship qualifications, practiced business improperly, behaved inappropriately, or possessed inferior racial characteristics. These forms of antisemitism, especially the racial one, all played key parts in the Holocaust. Without antisemitism, the Holocaust could not have happened.