The Spanish Inquisition was responsible for one of the fiercest repressions in human history. It fused the triple evil of a police state, a totalitarian ideology, and racial persecution. Its terrible reverberations have been felt in our own century, and are likely to be felt in the next. Yet for all its notoriety, its origins have never been fully explored or clearly understood before now. What caused this monstrous attack upon Spain's so-called conversos - the Christian descendants of the Jews who had been forced to convert during the anti-Semitic riots that swept across Spain at the end of the fourteenth century? Were the thousands of conversos who died at the hands of the Inquisition in fact secretly still Jews, only pretending to be good Christians, as the Inquisition charged and as most scholars continue to believe? In this magnum opus, the renowned scholar B. Netanyahu shows us that this claim is groundless. After a lifetime of research in long-unexamined Spanish sources, he reveals that at the time of the Inquisition, almost all conversos were in fact full-fledged Christians, and that the few Judaizers among them had dwindled into insignificance. The vast machinery of the Inquisition could not have been founded to kill a dying movement. What, then, was its purpose? The Origins of the Inquisition answers this question definitively. By examining Spanish anti-Semitism from its origins, Professor Netanyahu demonstrates that the brutal anti-converso movement that led to the Inquisition was the same one responsible for the massacre of Jews in Spain in 1391 and the ensuing mass conversion of Spanish Jews (at sword-point) to Christianity. The rapid rise of the conversos to high royal offices - higher, even, than those attained by their Jewish forefathers - made them the target of the same forces that had persecuted the Jews. It was to remove the conversos from their influential positions, and to prevent their intermarriage with the Spanish people, that they were accused of being secret Judaizers and members of a "corrupt" race that would "pollute" the Spanish blood. This was the first time that extreme anti-Semitism was wedded to a theory of race - a union that would dramatically affect the course of modern history.