Calas died on the wheel as a convicted murderer. The previous day, March 9, 1762, this Huguenot (French Protestant) was found guilty of murdering his son so as to prevent his conversion to Catholicism. A solemn burial service honored Calas’ son as a Catholic martyr.

French philosopher Voltaire, however, suspected that Calas had been a victim of Catholic intolerance. After proving that Calas’ son was actually a suicide, he launched a three-year campaign to arouse public opinion throughout Europe. Voltaire’s strategy worked. He finally succeeded in getting the French authorities to review the case, and on March 9, 1765, Calas was declared innocent posthumously. This glaring case of anti-Huguenot prejudice became one of the world’s causes célèbres. It prompted Voltaire to write his famous Treatise on Toleration.

[Picture on page 4]

Title page of first edition of Voltaire’s Treatise on Toleration, Paris, 1763