What political views did Napoleon spread in Europe that endangered monarchs?

Napoleon spread revolutionary ideals such as nationalism, secular governance, and the principles of the French Revolution, including liberty, equality, and fraternity. His military conquests dismantled feudal structures and promoted meritocracy, undermining the traditional power of monarchies. By establishing systems of civil law that emphasized individual rights and citizenship, he inspired uprisings and reform movements across Europe, threatening the legitimacy and stability of monarchic rule. These ideas ultimately contributed to the rise of liberal and nationalist movements that sought to challenge and replace absolute monarchies.