The balance of power in Europe in the eighteenth century was destroying itself The balance of power can be simply defined in modern terms as: a doctrine and an arrangement whereby the power of one state chalking up military victory after military victory and expanding French control over all of Europe and even into North Africa. By 1811, the French Empire controlled or had loyal regimes throughout Europe up to the Russian border.
The French Revolution changed the balance of power in Europe in that it introduced the concept of Republic as a type of goverment. Until that moment Europe had been ruled by monarchies whose kings and queens derived their power directly from God.
The French revolution came to overthrow this idea. It inagurated the era of the people as soveign ie. people had the right to decide who their goverment should be. The French Revolution paved the way for early modern democratic states.