Political map of Europe & the Mediterranean 5 November 1854 (Siege of Sevastopol): The Allies decided to destroy Russian power in the Black Sea by capturing the key naval base of Sevastopol, on the Crimean peninsula (Crimean War). While they were en route, Austria succeeded in pressuring Russia to withdraw from Moldavia and Wallachia. This could have ended the war, but the Allies sailed on to besiege Sevastopol (Siege of Sevastopol (1854%E2%80%931855)) and punish the Russians nonetheless.