The Principle of Legitimacy is a political doctrine that emerged after the Napoleonic Wars, advocating that legitimate rulers should be restored to power and that monarchies should be upheld as the rightful governing authority. This principle aimed to stabilize Europe by reinstating traditional monarchies and opposing revolutionary movements, reflecting the conservative ideals of the time. It was a key component of the diplomatic framework established during the Concert of Europe, which sought to maintain peace and order in post-Napoleonic Europe.