Why did European rulers denounce the French Revolution?

European rulers denounced the French Revolution primarily because they were afraid it would spread to their own countries. The revolution challenged the established order, promoting ideas of liberty, equality, and fraternity that posed a significant threat to monarchies throughout Europe. Rulers feared that revolutionary fervor could inspire similar uprisings among their subjects, leading to chaos and the potential downfall of their own regimes.

In the wake of the revolution, many monarchs formed alliances and coalitions to suppress the revolutionary ideals, as they believed that a successful revolution in France could lead to widespread instability and the erosion of their power. This fear transcended national borders and influenced the political landscape of Europe in the years that followed, prompting a reactionary movement among conservative monarchies to maintain their authority.