<P> As a spillover of the Enlightenment, nonsecular beliefs expressed first by Quakers and then by Protestant evangelicals in Britain and the United States emerged . To these groups, slavery became "repugnant to our religion" and a "crime in the sight of God ." These ideas added to those expressed by Enlightenment thinkers, leading many in Britain to believe that slavery was "not only morally wrong and economically inefficient, but also politically unwise ." As these notions gained more adherents, Britain was forced to end its participation in the slave trade . </P> <P> The leaders of the Enlightenment were not especially democratic, as they more often look to absolute monarchs as the key to imposing reforms designed by the intellectuals . Voltaire despised democracy and said the absolute monarch must be enlightened and must act as dictated by reason and justice--in other words, be a "philosopher - king". </P> <P> In several nations, rulers welcomed leaders of the Enlightenment at court and asked them to help design laws and programs to reform the system, typically to build stronger states . These rulers are called "enlightened despots" by historians . They included Frederick the Great of Prussia, Catherine the Great of Russia, Leopold II of Tuscany and Joseph II of Austria . Joseph was over-enthusiastic, announcing many reforms that had little support so that revolts broke out and his regime became a comedy of errors and nearly all his programs were reversed . Senior ministers Pombal in Portugal and Johann Friedrich Struensee in Denmark also governed according to Enlightenment ideals . In Poland, the model constitution of 1791 expressed Enlightenment ideals, but was in effect for only one year before the nation was partitioned among its neighbors . More enduring were the cultural achievements, which created a nationalist spirit in Poland . </P> <P> Frederick the Great, the king of Prussia from 1740 to 1786, saw himself as a leader of the Enlightenment and patronized philosophers and scientists at his court in Berlin . Voltaire, who had been imprisoned and maltreated by the French government, was eager to accept Frederick's invitation to live at his palace . Frederick explained: "My principal occupation is to combat ignorance and prejudice...to enlighten minds, cultivate morality, and to make people as happy as it suits human nature, and as the means at my disposal permit". </P>

The classical era has been called the age of enlightenment