Umberto Eco on The Protocols of the Elders of Zion:

Intellectual anti-semitism as we now know it originates from the modern world. In 1797, Abbé Barruel wrote his Mémoires pour servir à l’histoire du jacobinisme to show that the French revolution was a plot of the Knights Templar and the freemasons. Later it was an Italian, Captain Simonini, who suggested to him that it was above all the perfidious Jews who were acting behind the scenes. It was only after this point that the argument surrounding international Jewry began, and the Jesuits seized on it as an argument against the sects of the Carbonari. The controversy raged throughout Europe, but found its most fertile soil in France, where Jewish finance was now identified as an enemy to defeat. The controversy was certainly fuelled by Catholic legitimism, but it was in secular, political circles that the ill-famed Protocols of the Learned Elders of Zion slowly took shape. These were then published in Russian Tsarist circles and were finally used by Hitler. Guardian UK Books