Question

Why did Napoleon’s reign make European leaders eager to restore the monarchies?

Answer 1

Leaders believed the monarchs could help prevent any one ruler from taking too much power.

Answer 2

"Leaders believed the monarchs could help prevent any one ruler from taking too much power".

After witnessing the advent of Napoleon demonstration to capture Europe and their discernment of superiority, the leaders in Europe believed that kingships could be an alternative to evade that a personage such as Napoleon in the future.  They assumed that monarchies could bypass any other leader to control too much power as Napoleon did because Napoleon turned out to be more oppressive than any other monarchs could do.