In response to these actions Turkey declared war on Russia in October 1853 and requested Britain and France to send troops to the combat Russian moves against Constantinople. There were many underlying reasons for joining the conflict but the principal one was that Britain and France recognized the threat to Constantinople and sent naval units to the Black Sea in November. After the exchange of diplomatic notes without satisfactory results, war was declared in late March 1854. A joint command structure was created with Britain, France and Turkey each sharing command. These allies decided that the best strategy to thwart Russian ambitions was to seize Sebastopol, the Russian naval base at the southern end of the Crimean Peninsula.
British forces numbering about 30,000 reached Turkey in May 1854 and spent the month at Gallipoli before moving on to Varna where they remained until late August. On 14 September a joint invasion force of over 60,000 strong, comprised of British, French and Turkish elements landed in Calamita Bay, south of Eupatoria. The subsequent battles are described in Item 49f. The fighting continued for almost a year when the naval base of Sebastopol finally capitulated. Naval operations continued in the Baltic and in the Far East but the main fighting was over.
Peace negotiations began in 1856 at the Congress of Paris after Alexander II succeeded his father as Tsar. Among the results was an agreement by Russia and Turkey not to maintain naval or military bases on the Black Sea coast. In addition, all the Great Powers pledged to respect the independence and territorial integrity of the Ottoman Empire. The cost of these results was great -- French dead amounted to more than 30,000 in battle plus 75,000 to disease. The British lost nearly 4800 in battle and over 16,000 to disease. The Turks losses came to over 200,000. The kingdom of Sardinia also contributed 10,000 men to the conflict of which 2500 were lost to all causes. Russian fared worst of all -- their losses amounted to 522,000 with battle deaths ranging from 60,000 to 110,000.
By mid-19th century, the Ottoman Empire (Turkey) was in steep decline. The Russia of Tsar Nicholas I sought to exploit the situation by occupying the Turkish principalities of Moldavia and Wallachia (modern Romania) in 1853 which some saw to be in furtherance of their goal of seizing Constantinople and the Dardanelles. In addition, the Russians conducted several raids on Turkish harbours throughout that year.