Blood libel: A false belief which has endured since the 1st century BCE. It states that members of a religious group kidnap, abuse, ritually murder and sometimes eat the body of a member of another religion. Groups creating this groundless fable include ancient Greek and Roman Pagans, Christians, Nazis, and Muslims. Innocent religious groups victimized by the fable include Jews, Christians, Wiccans, Druids and other Neopagans, and Roma (Gypsies). The hoax exists today mostly among some Muslims (against Jews) and some Fundamentalist Christians (against Wiccans, Satanists and other religious minorities).

In 1144 CE, an unfounded rumor began in eastern England, that Jews had kidnapped a Christian child, tied him to a cross, stabbed his head to simulate Jesus' crown of thorns, killed him, drained his body completely of blood, and mixed the blood into matzos (unleavened bread) at time of Passover. The rumor was started by a former Jew, Theobald, who had become a Christian monk. He said that Jewish representatives gathered each year in Narbonne, France. They decided in which city a Christian child would be sacrificed.

... The myth shows a complete lack of understanding of mainline Judaism. Aside from the prohibition of killing innocent persons, the Torah specifically forbids the drinking or eating of any form of blood in any quantity. However, reality never has had much of an impact on blood libel myths. This rumor lasted for many centuries; even today it has not completely disappeared. 1

Pope Innocent IV ordered a study in 1247 CE. His investigators found that the myth was a Christian invention used to justify persecution of the Jews. At least 4 other popes subsequently vindicated the Jews. However, the accusations, trials and executions continued. In 1817, Czar Alexander I of Russia declared that the blood libel was a myth. Even that did not stop the accusations against Jews in that country.

"Holy shrines were erected to honor innocent Christian victims, and well into the twentieth century, churches throughout Europe displayed knives and other instruments that Jews purportedly used for these rituals. ..." 7

Nicholl reports that "there are 150 recorded cases of the charge of ritual murder, and many led to massacres of the Jews of the place." 2

Some of the incidents were: ...

Blood libel (also blood accusation[1][2]) refers to a false accusation or claim[3][4][5] that religious minorities, in European contexts almost always Jews, murder children to use their blood in certain aspects of their religious rituals and holidays.[1][2][6] Historically, these claims have – alongside those of well poisoning and host desecration – been a major theme in European persecution of Jews.[4]