The Congress of Vienna (1814-1815) and the Concert of Europe (a system established after the Congress to maintain the balance of power in Europe) had several impacts, both positive and negative. One of the notable negative impacts was that they suppressed nationalist and liberal movements across Europe.
While the Congress aimed to restore stability and conservatism after the upheaval of the Napoleonic Wars, its focus on maintaining the status quo and preventing revolutionary change often stifled the aspirations for national self-determination, liberal governance, and democratic reforms. This suppression led to frustrations and discontent in various regions, contributing to a series of uprisings and revolutions throughout the 19th century, such as the Revolutions of 1848.
In summary, a significant negative impact of the Congress of Vienna and the Concert of Europe was their suppression of nationalist and liberal movements, which led to unrest and conflict in various parts of Europe.