For centuries, one central goal of Russian foreign policy was to obtain a warm water port in the south--namely, at the Bosporus Straits and the Strait of the Dardanelles, the small waterways connecting the Black Sea to the Aegean and Mediterranean Seas. In 1854, the decaying Ottoman Empire controlled that essential waterway and Russia sought increased power in this region.
In 1853, St. Petersburg demanded that the Ottoman Empire recognize Russia's right to protect Eastern Orthodox believers in Turkey. When Turkey refused, Russia sent troops into Ottoman territory. Fearing increased Russian power and an upset to the balance of power on the Continent, Great Britain and France declared war on Russia on March 28, 1854. Russia fared well against its weaker neighbor to the south, destroying the Turkish fleet off the coast of Sinope, a port city in north-central Asia Minor. However, in September 1854, the British and French laid siege to Sevastopol, Russia's heavily fortified chief naval base in the Black Sea, lying on the Crimean peninsula. After just under one year of constant battle, the Russian abandoned the fortress, blowing up their fortifications and sinking their own ships. Meanwhile, at nearby Balaklava, British troops charged down a narrow valley that was flanked by Russian guns on both sides. Nearly every British soldier fell dead in what came to be called the Valley of Death. The name of the British group was the Light Brigade, giving rise to the famous Alfred, Lord Tennyson poem, "The Charge of the Light Brigade."
Russia's new tsar, Alexander II, sued for peace in 1856. In the resulting Peace of Paris, Russia relinquished its claim as Christian protector in Turkey, the Black Sea was neutralized, and the balance of power was maintained.
The Crimean War had the highest casualty rate of any conflict in Europe between 1815 and 1914, the century-long peace maintained by the balance of power. Disease killed many, but poor leadership killed thousands more. It was the final war in which the Ottoman Empire had any victorious role, though even in the Crimea, Russia fared quite well against the Turks. The greater importance of the Crimean War is embodied in one international and one national element.
In terms of European international relations, the Crimean War marked the end of the veritable charade of Russian military dominance on the Continent. Granted, the Russian army was the largest force due to its sheer numbers; however, it was soundly defeated by smaller British and French forces, and its navy proved utterly useless and backward by the middle of the nineteenth century. It was Russia who guaranteed to maintain order and balance after the defeat of the Napoleon--it did so with Austria, Prussia, and France since then. Now, that power was effectively eliminated; therefore, the demise of the balance of power could not be far behind.
On the national scale, the Crimean War, some historians have argued, marked the beginning of the road to the Russian Revolution of 1917. (See the Russian Revolution SparkNote.)