An interesting explanation of the Passion Plays (from: http://www3.sympatico.ca/glancy.nelson/cj-holy-week-and-the-jews.html, now disappeared )

Biblical Theology: for Study and Life
Reverend Glen Nelson

Holy Week and the Jews

… One historian writes that during the late Middle Ages, “practically every hamlet from Italy to England felt constrained to offer its version of the biblical tale at Easter.” Another remarks that “the life of the city stopped, shops were closed, convents and monasteries were deserted; entire populations gathered for several days for ‘the shows.'”

These Passion Plays were embroidered and elaborated over the years, and one of the tragic developments was the representation of Jews as the villains. In one passion play, which lasted two days, the first day was a lengthy discussion by devils about their plot to kill Jesus, a plot ultimately assigned to the Jews who were eager to cooperate. The next day’s action included a lengthy (700 lines) horrendous description of the crucifixion, with Jews enthusiastically wielding the hammer and taunting Jesus. “Around the cross Jews whirl in a dance of abandon and joy, mocking their victim.”

The emotions of rage worked up by such vivid drama were sometimes intensified by the clergy. A description of a sermon by a Bishop included these words, “…they could observe around them the grandchildren of those who condemned Jesus [i.e. Jews] …when their hearts were agonized by the thoughts of the insults offered to their Saviour, they had his [the Bishop’s] blessing, and the Governor’s license to revenge themselves upon the Jews – but only with stones.”
The homes of Jews were then bombarded by stones all week, a practice that was officially abolished in the 12th century, but was still being followed a century later. This visitation of Christian anger on Jews was not always limited to stone throwing. One historian described these Holy Week scenes this way, “In total identification, the crowds lived Christ’s agony, transferring their rage to the tormenters with a real massacre following the depicted one.
The authorities often tried to protect Jews from this rage of the people. Indeed, Passion Plays were banned in Rome in 1539 because they were regularly followed by the sacking of the Jewish ghetto along the Tiber River. Pope Innocent IV tried (but failed) to stem the tide of accusations of ritual murder against the Jews, a slander that began on the eve of a Good Friday in England when the body of a child was discovered and the story invented that Jews killed a Christian on Good Friday to mock Jesus’ crucifixion. But at other times the authorities reflected the popular mood, as in this example of medieval Spanish law, “We also forbid any Jew to dare to leave his house or his quarter on Good Friday, but they must all remain shut up until Saturday morning; if they violate this law, we decree that they shall not be entitled to any reparation for any injury or dishonor inflicted upon them by Christians.”
……

Glen Nelson
March 2000