It all started with the Greek conquest of the Middle East and the way Greeks ruled Palestine. Jews and Greeks irritated each other constantly. Greeks put up statues - worse yet, statues of nude men and women - all over the place. Jews believed that sinful acts like idolatry poisoned the land, not just morally but also literally. Greeks held athletic events in which boys wrestled nude, another thing that deeply offended Jews. Individuals who wanted to establish friendships couldn’t get past the hurdle of Kosher dietary laws, which meant that Jews and Greeks couldn’t eat together. Sharing meals is one of the most ancient way to establish friendships. Jews rebelled against Greek rule, so they were ‘troublesome’ and ‘stubborn’.
Jews couldn’t accept Jesus as the Messiah, because they were looking for another Alexander the Great to free them from Roman rule. Romans had their own problems with Jews. To call the Romans heavy handed is an understatement, and they rubbed Jews much like the Greeks did. The result was at least two major rebellions - again the Jews were labeled troublesome and stubborn. By about the year 100 Christians decided Jews were heretics for refusing Jesus,and that charge only dissipated in the latter half of the 20th century.
As heretics, it was permissible to rob them, beat them, make all kinds of punitive laws against them, and to hound them mercilessly. In Europe Jews were usually barred from owning land. Catholic law banned the charging of interest for loans, which meant borrowing money from Catholics was pretty difficult. Judaism has no such ban, so Jews became money lenders. Kings routinely racked up big debts, then defaulted on the loans or simply stole all their money and drove them out of the realm. Popular opinion said that Jews sacrificed babies, poisoned wells, caused plagues, and so on. If Jews were poor they deserved it. If they were middle class they didn’t deserve it, and if they were rich they could only get that way through fraud and extortion. In other words, Jews couldn’t do anything right.
About 1895 the Russian secret police published a vicious and false propaganda piece called “The Protocols of the Elders of Zion,” which claims that Jews are planning on taking over the world. Millions of Europeans believed this, and this document was fundamental to Nazi propaganda.