In 1815, the Battle of Waterloo took place. Which European political order was restored afterward?

The story behind the answer

Waterloo (June 18, 1815) came nine days after the Congress of Vienna’s Final Act (June 9), so nothing was literally “restored” that day. Rather, Napoleon’s defeat cleared the way for the great powers to enforce the Vienna settlement through a cooperative system of congresses and balance-of-power management commonly called the Concert of Europe. This framework sought to prevent another hegemon and to contain revolution through collective consultation and, at times, intervention.

For context, the Bourbon Restoration in France and the 1814/1815 Treaties of Paris were parts of the settlement; the Quadruple Alliance underpinned its enforcement; and the Holy Alliance (Sept. 1815) was a separate, more rhetorical pledge by monarchs. The intended idea is that Waterloo consolidated the Vienna/Concert system, which then guided European diplomacy at meetings like Aix-la-Chapelle (1818), Troppau (1820), Laibach (1821), and Verona (1822).