Blood Libel

Blood libel or ritual murder libel is an antisemitic canard which falsely accuses Jews of murdering Christians in order to use their blood in the performance of religious rituals. Echoing very old myths of secret cultic practices in many prehistoric societies, the claim, as it is leveled against Jews, was rarely attested to in antiquity. According to Tertullian, it originally emerged in late antiquity as an accusation made against members of the early Christian community of the Roman Empire. (Wikipedia)