The Crimean War begins when the Ottoman Empire declares war on the Russian Empire.

The Crimean War was fought between Russia and an alliance of the Ottoman Empire, France, the United Kingdom, and Sardinia from October 1853 to February 1856. Geopolitical causes of the war included the Eastern question, the expansion of Russia in the preceding Russo-Turkish wars, and the British and French preference to preserve the Ottoman Empire to maintain the balance of power in the Concert of Europe.