Johannes (Josef) Pfefferkorn (1469 – 1523) was a Jewish-German Catholic theologian and writer who converted from Judaism. Pfefferkorn actively preached against the Jews and attempted to destroy copies of the Talmud, and engaged in a long running pamphleteering campaign against and with Johann Reuchlin.
Born a Jew, possibly in Nuremberg, Pfefferkorn moved to Cologne after many years of wandering. After committing a burglary, he was imprisoned and released in 1504. He converted to Christianity in 1505 and was baptized together with his family.
In Der Judenspiegel (Cologne, 1507), he demanded that the Jews should give up the practice of usury, work for their living, attend Christian sermons, and do away with the Books of the Talmud. On the other hand, he condemned the persecution of the Jews as an obstacle to their conversion, and, in Warnungsspiegel, defended them against charges of murdering Christian children for ritual purposes. In a pamphlet, Warnungsspiegel, he pretended to be a friend of the Jews, and desired to introduce Christianity among them for their own good. He urged them to convince the Christian world that the Jews do not need Christian blood for their religious rites and advocated seizing the Talmud by force from them. "The causes which hinder the Jews from becoming Christians," he wrote, "are three: first, usury; second, because they are not compelled to attend Christian churches to hear the sermons; and third, because they honor the Talmud."
Bitterly opposed by the Jews on account of this work, he virulently attacked them in: Wie die blinden Jüden ihr Ostern halten (1508); Judenbeicht (1508); and Judenfeind (1509). In his third pamphlet he contradicted what he had written earlier and insisted that every Jew considers it a good deed to kill, or at least to mock, a Christian; therefore he deemed it the duty of all true Christians to expel the Jews from all Christian lands; if the law should forbid such a deed, they do not need to obey it: "It is the duty of the people to ask permission of the rulers to take from the Jews all their books except the Bible...." He preached that Jewish children should be taken away from their parents and educated as Catholics. In conclusion he wrote: "Who afflicts the Jews is doing the will of God, and who seeks their benefit will incur damnation."
In the fourth pamphlet, Pfefferkorn declared that the only way to get rid of the Jews was either to expel or enslave them; the first thing to be done was to collect all the copies of the Talmud found among the Jews and to burn them.
Through the help of the Elector and Archbishop of Mainz, Uriel von Gemmingen, the Jews asked the emperor to appoint a commission to investigate Pfefferkorn's accusations. A new imperial mandate of 10 November 1509, gave the direction of the whole affair to Uriel von Gemmingen, with orders to secure opinions from the Universities of Mainz, Cologne, Erfurt, and Heidelberg, from the inquisitor Jakob Hochstraten of Cologne, from the priest Victor von Carben, and from Johann Reuchlin. Pfefferkorn, in order to vindicate his action and to gain still further the good will of the emperor, wrote In Lob und Eer dem allerdurchleuchtigsten grossmechtigsten Fürsten und Herrn Maximilian (Cologne, 1510). In April he was again at Frankfort, and with the delegate of the Elector of Mainz and Professor Hermann Ortlieb, he undertook a new confiscation.
Hochstraten and the Universities of Mainz and Cologne decided in October 1510 against the Jewish books. Reuchlin declared that only those books obviously offensive (as the Nizachon and Toldoth Jeschu) would be destroyed. The elector sent all the answers received at the end of October to the emperor through Pfefferkorn. Reuchlin reported in favor of the Jews, and on May 23, 1510, the emperor suspended his edict of 10 November 1509, and the books were returned to the Jews on June 6.
Diarmaid MacCulloch writes in his book The Reformation: A History (2003) that Desiderius Erasmus was another opponent of Pfefferkorn, on the grounds that he was a converted Jew and therefore could not be trusted.