An idea began to form in the British Parliament (i.e. However, instead of retuning Dresden to Prussia, I liberated it into the new and loyal country of Saxony.
They saved Berlin from Russian forces, then pressed slowly eastward, re-capturing the Prussian city of Dresden. The vast armies I had left on the continent, instead of returning home triumphant, would be pressed into service once more (the men denied leave despite fighting essentially a world war over 6 years- not a popular move). Only, immediately on performing this feat (signed and agreed by all parties in the Treaty of Budapest no less), Russia invaded East Prussia and ignited a huge war of conquest again! How should I react to this? Leave Europe to once again suffer the ravages of war? Leave Prussia to be hopelessly steamrolled despite being a loyal ally against the French? Most of Central Europe to Prussia, Southern Europe and Balkans to Austria, and the East to Russia, while I held onto France and Spain. Once I'd destroyed his armies and captured his final city, in Hungary of all places, I was left with a huge continental empire, and decided I should return the provinces to those they were captured from in the first place. I started my British campaign by completed a huge, traditional Total War-style campaign of conquest, against the sprawling French Empire of Napoleon.
The year is now 1830, and there are no wars and haven't been for 30+ turns. This one took a while, but I created a world filled with peace, harmony and trade, with every nation state capable of being unlocked in the game ruling their own destiny- almost all as a British protectorate.