They made the European community unite against Napoleon.
One the one hand , we have the revolutionary vision of Napoleon of bringing new ideas into neighbouring and distant European nations. Napoleon himself declared_"I wished to found a European system...a European Code of Laws, ..: there would be but one people in Europe," With the Napoleonic Wars, the nations had to assemble in order to balance power, thus, giving birth to famous treaties and conventions such as the Treaty of Paris and Vienna. With increasingly many political opponents, the Europeans tried to banish the specter of Napoleon and its influence so either from the perspective of Napoleon or his opponents, a common European space was born.
