In a opinion piece in the Times, Daniel Finkelstein writes about why there were accusations of antisemitism in a front article of the daily telegraph about George Soros funding a anti brexit campaign. As an example of fictitious Jewish conspiracies fueling antisemitism he writes that the black death lead to pogroms against Jewish people because communities believed they caused the black death.
Where and when did the blaming start and did further outbreaks lead to more pogroms?
Plague pogroms occurred in regions containing Jewish communities during the plague pandemic of the mid-14th century, the Black Death. Antisemitic violence against Jewish individuals and communities is well-documented prior to the plague of 1347, but the plague presented a pretext for blame at a time when social conditions were particularly raw. Anti-Jewish persecutions accompanied the passage of the plague itself -- through Italy, into France, Spain, and Portugal, into Switzerland, Germany, and the Low Countries, and into England and Scandinavia. Antisemitic violence was found in all of these countries, barring England -- not because the English harbored unusual goodwill toward Jewish communities but because the Jewish population in England had already been expelled decades earlier. The premise that plague is a consequence of Jews poisoning community wells had appeared by at least 1319 in German-speaking Franconia, and not coincidentally a center of anti-Jewish activity seems to have been in German-speaking areas. In a late medieval pandemic context, marginalized individuals were scapegoated; Jewish communities were highly visible, as well as associated in the Christian imagination with purely malicious crimes like poisoning wells and murdering children. In addition to scapegoating, the timeframe around the Black Death was also pretty much the perfect storm of economically motivated resentment and apocalyptic religious thought. The result was not only haphazard peasant violence (the stereotypical image of the angry mob) but also persecution formalized and encouraged by local authorities.
Later outbreaks of plague stopped short of continent-wide pandemics, but were also accompanied by their own persecutions, albeit on a smaller scale. The disruptions of the Black Death were experienced as positively apocalyptic, and this severe state of frenzy that ensued with its religious overtones might have fueled the brutality recorded as inflicted on Jewish communities, as not merely enemies of Christian communities but embodiments of evil. In later 16th century contexts where the primary social conflict had shifted due to the Reformation, religiously-motivated scapegoats also shifted -- in addition to Christians as a group blaming Jews, Protestants could also blame Catholics, and vice versa. (For instance, in one outbreak of plague in a region under religious tension, German Lutherans accused Jesuits of spreading plague via sorcery and the evil eye; Jesuits accused German Lutherans of spreading the plague by means of active biological warfare, smearing contaminated agents on the door handles of their enemies' residences.) However, these exchanges of plague-related blame between Christian denominations generally did not erupt into wide-scale murderous violence or the routing of whole communities in the way hostility aimed at Jewish people did. The anti-Jewish mass violence of the Black Plague era were not isolated instances of violence without precedent -- medieval pogroms occurred even in the absence of plague conditions, as did other anti-Jewish legislation and expulsions -- but they were above and beyond the norm.
Some reading: