Answer: Congress of Vienna (1814-1815) aimed re-establishment of pre-1789 order in Europe. It meant especially return of overthroned dynasties to European monarchies (principle of legitimacy). Bourbons were coming back to France, Spain, Naples etc.
Explanation: Congress of Vienna was organized by count Metternich (Austrian chancellor) and initiated so-called "congress politics"....congresses regullarly took place when this Vienna´s order was threatened. This was the policy of Saint Alliance. This order lasted till 1830 (July Revolution in Paris that dethroned last Bourbon, Charles X), then it was significantly weakened. Metternich ruled in Austria till 1848.