Medieval Christians were suspicious of Jewish culture and practices. Prejudices occur and grow when persons of different cultures don't have honest interactions with each other. In the Middle Ages, European culture was dominated by the Catholic Church, and Jews were considered very strange and alien. There also were religious prejudices against the Jews, whom the Christians blamed for killing Jesus, their Savior. The medieval suspicion against Jewish culture and practices even came up with bizarre ideas and accusations against them. During the Black Death, Jews were blamed for poisoning the wells with disease (as a way of trying to explain how the plague was spreading). There was even an accusation that has been called "the blood libel," which said that Jews used the blood of Christians to make the matzah bread for their Passover rituals.
Hatred of Jews, which later came to be known as Anti-Semitism, grew throughout the Middle Ages and has persisted into modern times.
