the scapegoating of tolerance itself.....

     A very different kind of external force may also have played a decisive negative role.  The devastating Black Death, the bubonic plague that swept through Europe and decimated its populations in the middle of the fourteenth century, provides the most solid conventional explanation of the rise of religious intolerance on the Iberian Peninsula - as well as throughout the rest of medieval Europe.  The nearly unimaginable upheavals and despair triggered by the sudden death of upwards of twenty percent of the overall population were most vividly described by the contemporary Italian writer Giovanni Boccaccio.  The Decameron, his masterpiece, which was written shortly after the height of the plague, in 1348, begins with a description of the horrors of the plague.  The physical ravages were terrible enough, but far more telling was the utter destruction of the social mores and civic standards that were (and are) the backbones of any civilization, the devastated communal and familial structures that followed the fast-spreading illness.  Bodies were thrown into the streets and most people died alone, abandoned by terrified and helpless family and friends.  This catastrophic and wholesale undermining of the social and religious order resulted, among other things, in the scapegoating of certain minority communities - the Jews conspicuously so - as well as in the scapegoating of tolerance itself.  In answering the question of why God would countenance the near-destruction of His people, it was easy enough for certain voices to claim, echoing Scripture itself, that society was surely being punished for its lack of true belief, as well as for the tolerance of nonbelievers in its midst.

-Maria Rosa Menocal,  Ornament Of The World:  How Muslims, Jews, And Christians`Created A Culture of Tolerance in Medieval Spain