The misery of the working classes presented in itself reason enough for revolution; but revolution only comes when there are men of ideas to lead the unlettered masses. In France the educated classes entertained revolutionary ideas, and the men of letters who promulgated those ideas became the leaders of opinion, and exerted enormous influence over their own and the following generations. First came the Voltairians, led by Voltaire (1694–1778). During the century rapid advance was being made in all branches of study--in history, jurisprudence, mathematical and physical science. The idea of progress was definitely conceived, and knowledge upheld as the chief factor in producing virtue and happiness. For the increase and diffusion of knowledge the recognition of two principles was indispensable--religious toleration and the freedom of the press. Both these principles were, however, in direct antagonism to the principles on which the authority of the Roman Catholic Church was based--unity of faith and worship, the subordination of philosophy and science to theology, the submission of reason to the teaching of tradition. Protestant clergymen were put to death as late as 1762; while in 1765 a lad convicted of sacrilege was hanged, and his body afterwards burned. Such acts of intolerance and cruelty were, however, condemned by public opinion, and, between the Church and the exponents of the new ideas, violent collision inevitably ensued. Voltaire made it the work of his life to destroy belief in revealed religion. In verse and in prose, in historical works, in letters and pamphlets by the dozen, with rude licence or sham respect, he held up the Church to derision, indignation, and contempt, as the great enemy of enlightenment and humanity. ‘The most absurd of empires,’ he wrote, ‘the most humiliating for human nature, is that of priests; and of all sacerdotal empires, the most criminal is that of priests of the Christian religion.’ ♦Encyclopædists.♦