So why did the allies not pursue a peace once the Russians had left the principalities? Why did they decide to invade Russia when the war against the Russians had been won? Why was there a Crimean War at all? The allied commanders were frustrated by the retreat of the Russians. Having brought their armies all this way, they felt they had been ‘robbed of victory’, as Saint-Arnaud put it, and wanted to achieve a military goal to justify the efforts they had made.