The Crimean War (1853-1856) was a brutal conflict that took its name from the Crimean Peninsula on the Black Sea. The war, which claimed an estimated 650,000 lives, pitted Britain, France, Turkey and Sardinia against Russia, whose ruler, Czar Nicholas I, was attempting to expand his influence over the Middle East and the eastern Mediterranean at the expense of the declining Ottoman Empire. The British and French, in turn, saw Nicholas’ power grab as a danger to their trade routes, and were determined to stop him.

The event is commonly remembered today as the setting for Alfred, Lord Tennyson’s poem “The Charge of the Light Brigade,” which glowingly depicts the bravery of a British cavalry unit that suffered horrific casualties when it made an ill-advised attack on a heavily-defended enemy position. It’s also the conflict in which Florence Nightingale, the founder of modern nursing, first became famous, for her efforts to help wounded British soldiers who were dying of cholera and typhoid in squalid hospital wards.

Religious Tensions Spark the War

The spark that set off the war was religious tension between Catholics and the Orthodox believers, including Russians, over access to Jerusalem and other places under Turkish rule that were considered sacred by both Christian sects. After violence in Bethlehem in which Orthodox monks were killed, Nicholas sent an emissary to the Turkish sultan, Abdulmecid I, and demanded not only equal access to religious sites but that the sultan recognize Nicholas as protector of Orthodox Christians throughout the Ottoman empire, as British journalist and author A.N. Wilson has written.

After the sultan refused his request, Nicholas—who viewed Turkey as the “sick man” of Europe—decided to occupy the Turkish-controlled principalities of Moldavia and Walachia (territory that today is part of the nation of Romania). In response, in October 1853, Turkey declared War on Russia and counterattack Russian forces.

Though the Turks won some initial victories, the fight was lopsided in Russia’s favor. A month after the war began, Russian gunships pounded an antiquated Turkish naval force at ships at the Black Sea port of Sinop, setting their wooden hulls on fire with incendiary shells and killing nearly 2,000 Ottoman sailors and officers, according to Candan Badem’s 2010 book The Ottoman Crimean War. That horrible slaughter helped inflame western European public opinion against the Russians.

The British and French Enter the War

Russia’s aggressiveness also made the British nervous about maintaining their trade with Turkey and access to India. Meanwhile, the French, who still remembered Napoleon I’s defeat by the Russians, saw a chance to take revenge. The two countries entered the war on Turkey’s side in late March 1854. With the combined might of their navies and armies—including a 60,000-man force protecting Istanbul, the Turkish capital—they expected to make short work of the Czar’s military.

In mid-September 1854, the allies landed 30,000 French soldiers, 26,000 British troops and 4,500 Turks at Eupatoria, a town on the Crimean peninsula. The plan was to march south and capture Savastopol, a heavily-fortified port city that served as the main naval base for Russia’s Black Sea fleet. A few days later, the allies took on the Russians at the battle of the Alma, which ended just three hours later with the Czar’s forces being routed. More than 5,700 Russian soldiers were killed, while the British and French lost 962 men, according to the Lancashire Infantry Museum.

The Allies then headed to Sevastopol for what they expected to be a three-month siege. Instead, the fighting ended up dragging on for nearly a year.

British Infantrymen Hold ‘Thin Red Line’

Early on, the Russians tried to break through British lines and capture an allied base at Balaklava, a harbor that was crucial to supplying the allied operation. The British were compelled to divert some of their forces to go on defense. In the October 1854 Battle of Balaklava, the Russian cavalry’s advance was met by the British 93rd Highland Regiment of Foot, whose commander, Field Marshal Sir Colin Campbell, told his men there was no question of retreat. Instead, he instructed, “you must die where you stand,” unless they managed to repel the charging Russian horsemen.

Campbell’s “thin red line” of infantrymen remarkably, did just that, keeping their cool and firing disciplined volleys. The Heavy Brigade, a force of 800 British cavalrymen, then pursued the Russians, throwing them into disarray.

But that success was overshadowed by the British blunder that followed. To prevent the Russians from moving captured artillery, British Field Marshal Lord Raglan ordered another cavalry unit, the Light Brigade, to go in and seize them. But one of his officers, George Bingham, the earl of Lucan, became confused about which guns Raglan was talking about. The result was that the Light Brigade—led by Lord Lucan’s brother-in-law James Brudenell, the earl of Cardigan—rode off to attack the wrong artillery battery, one that was situated in a well-defended valley where the Russians could fire upon them from three sides.

As Lord Cardigan later described, “When we came to with a distance of fifty yards from the mouths of the artillery which had been hurling destruction upon us, we were, in fact, surrounded and encircled by a blaze of fire, in addition to the fire of the riflemen upon our flanks.” Of the Light Brigade’s 670 soldiers, 110 were killed and 160 were wounded, and the unit lost 375 of its horses as well.

In desperation, the Russians tried another surprise attack in November, but again failed. The Battle of Inkerman was fought in the terrifying confusion of a thick fog, which forced small groups of British soldiers to advance blindly toward gunfire and fight the Russians wherever they found them. The Russians couldn’t see the Allied force, and never realized that they were badly outnumbered. Ultimately, the Russians retreated, but not before leaving behind 12,000 dead, while the British lost 2,500 men and the French 1,700.

But the allies faced other obstacles besides the Russians. In the winter of 1854-55, a severe storm battered the Crimean peninsula, destroying the British army’s tents and sinking ships carrying medical supplies, food and clothing, and soldiers had to man trenches in freezing cold, and many succumbed to diseases such as cholera.

Russia Backs Down, Tensions Continue

The besieged Russians suffered too, and eventually their resolve gave out. In the summer of 1855, after two unsuccessful assaults and a lengthy bombardment, in early September French soldiers overwhelmed the Russians in hand-to-hand combat and raised their flag over the Malakoff Redoubt, a key fortification in Sevastopol’s defenses. A few days later, the Russians burned their remaining ships in Sevastopol and withdrew from the city.

With the Austrians threatening to join the war on the allied side, the Russians finally decided they’d had enough. They agreed to end the war, and the Treaty of Paris was signed in March 1856. Russia agreed to give back the territory it had seized, and the Black Sea was demilitarized. But peace had come at an enormous cost, and tensions between the Russians and the Turks continued for decades. The two empires eventually squared off on opposite sides in World War I—an even bloodier conflict that neither Czarist Russia nor the Ottoman Empire survived.

The Crimean War in some ways was the first modern technological conflict, according to The Institution of Engineering and Technology. For the first time, soldiers used rifles that were mass-produced in factories, and landed on coastlines in armored assault vessels. British and French forces communicated between the Crimea and headquarters in Paris via telegraph lines, and built railroad lines to transport supplies and ammunition.

The war also indirectly led to an even bigger breakthrough. After British industrialist Henry Bessemer developed a new, more powerful and accurate type of artillery shell, he discovered that the then-standard cast-iron naval gun barrels couldn’t handle the forces his projectiles generated. After the war, Bessemer patented a process for mass production of steel, which became an essential material in modern warfare.