What two European countries gained the most power after congress of Vienna?

The two European countries that gained the most power after the Congress of Vienna were Great Britain and Austria.

Great Britain had emerged from the Napoleonic Wars as the world's leading naval and economic power. It controlled a vast empire and had significant influence over European affairs. Austria, on the other hand, had regained its pre-war status as a major power in Central Europe.

The Congress of Vienna re-established the European balance of power, which had been severely disrupted by the French Revolution and the Napoleonic Wars. It also created a new concert of Europe, whereby the major powers would consult with each other to prevent future wars and maintain peace. Great Britain and Austria were both instrumental in the creation of this new order, and they would continue to play a leading role in European affairs for decades to come.