The Crimean War was fought between the Russian Empire and an alliance of the Ottoman Empire, the Second French Empire, the United Kingdom of Great Britain and Ireland, and the Kingdom of Sardinia-Piedmont from October 1853 to February 1856. Geopolitical causes of the war included the Eastern question, expansion of Imperial 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.