The third modern notion which has transformed Europe is the recognition of the principle of personal and individual liberty. Feudalism left the impress of its graduation of rights and duties marked deeply on the constitutions of the European States. The sovereignty of the people implies political liberty of action; feudalism denied the propriety and advantages of social and economical freedom. Theoretically, freedom of individual thought and action was acknowledged to be a good thing by all wise philosophers and rulers. Practically, the poorer classes were kept in bondage either as agricultural serfs by their lords or as journeymen workmen by the trade-guilds. Where personal and individual liberty had been attained, political liberty became an object of ambition, and political liberty led to the idea of the sovereignty of the people. The last vestiges of feudalism were swept away during this era of transition. The doctrines of the French Revolution did more than the victories of Napoleon to destroy the political system of the eighteenth century. The Congress of Vienna in 1815 might return to the former notions of government and the State, but it did not attempt to restore the old restrictions on individual liberty. With personal freedom acknowledged, the reactionary tendency of the Congress of Vienna was left of no effect. Liberty of thought and action led to the resurrection of the conceptions of nationality and of the sovereignty of the people, which were but for the moment extinguished by the defeat of France in the person of Napoleon by the armies of united Europe. [Sidenote: The Benevolent Despots.]