In 1670 however, the "Chambre de l'Édit" was transferred to Castelnaudary, much to the discontent of even the catholic citizens of Castres, who lost a major source of business and revenue with the departure of the lawyers and the plaintiffs. The Revocation of the Edict of Nantes soon followed, and Castres suffered greatly when many Protestants chose to go into exile. Then came the plague of 1720-1721 and the fire of 1724. Last but not least, Castres lost its liberal charter in 1758. In the 1760s, a few years after the famous Calas Affair in Toulouse, Castres made the headlines nationwide: Pierre-Paul Sirven and his wife, both Protestants, were wrongly accused of having murdered their daughter in order to prevent her from converting to Catholicism. Tried and sentenced to death "in absentia" on March 29, 1764, they were defended by Voltaire, and eventually exonerated in 1771.