25 Bloodiest Military Campaigns In History

Posted by , Updated on March 21, 2024

Wars have been fought for a variety of reasons including land, power, honor, freedom, and religion. And although many wars are certainly remembered for their influence on the course of history, their most painful memory is always the cost to human life. So, from the battlefields of ancient Greece to the jungles of Vietnam these are the 25 bloodiest military campaigns in history.



The Wars of Alexander the Great


King Alexander III of Macedon was considered one of the greatest military commanders of all time as he was undefeated in the battle. At the time of his death, he had conquered most of the known world for Greece and left millions of casualties behind.+


The Battle of Kalinga by the Mauryan Empire


The battle of Kalinga is one of the largest battles ever to be fought on the Indian subcontinent. It was between Ashoka the Great of the Mauryan Empire and the feudal republic of Kalinga which was defeated due to Ashoka’s brutal strength. Interestingly enough, however, the brutality of the bloodshed led Ashoka to Buddhism.


The Battle of Salsu


The battle of Salsu was a huge battle between the Sui Dynasty of the Chinese and the Korean Kingdom of Goguryeo. In 612, the Sui Dynasty deployed over one million men to invade Goguryeo who defiantly resisted the Chinese. The Korean military defended their fortress against the Chinese army and navy for several months by drowning thousands of Sui’s men. The Goguryeo Cavalry pursued the remaining Sui forces that retreated to the Liaodong peninsula.


The Battle of the Badger Mouth


The fighting between the Mongolian Empire and the Jin Empire escalated when Genghis Khan insulted and enraged Emperor Weishaowang in his statement that the latter was unfit to be an emperor and a leader because he was a coward. He further fueled the fire by adding that an emperor should be a man from the sky like him. This news spread quickly to both their armies and resulted in numerous campaigns including the battles at Wushabao, Datong, the Badger Mouth campaign, and the battle of Guihebao. It only ended with the Mongol occupation of Juyongguan, but the campaigns resulted in the deaths of 500,000 people or more.


Mongol Invasions


Building off what we just talked about, the Mongolian Empire was one of the largest to ever exist on the face of the planet. It was so vast that it’s territory comprised 20% of the Earth’s land. When it comes to ruthlessness, no one could outdo the bloodthirsty Mongolian armies under Genghis Khan, and the bloodshed was so great that according to legend 100,000 Chinese citizens once committed mass suicide just to avoid them.


The Shi Rebellion


The An Shi rebellion was brought about by the deception of An Lushan, a general favored by the emperor. The rebellion, which lasted for most of the latter Tang Dynasty in China, had an estimated death toll of 36 million. As the Tang Dynasty lost its power to contain the rebellion, the emperor became a puppet, which also provided an opportunity for foreign groups to raid its territory.


The Conquests of the Ming Dynasty


Though recognized as one of the greatest and most established dynasties in history, the Ming Dynasty was conquered when a Manchurian leader named Nurchaci seized control of the Manchurian tribes in China and demanded the dynasty to pay him tribute. The open defiance led to war and both parties fought for a number of years until Beijing was captured by the rebels in 1644. Groups that are still loyal to the Ming Dynasty existed even until the creation of the Republic of China in 1912. The battles between the two cost the lives of 25 million people in both the military and civilian population.


The Second Punic War


Known to the Romans as “The Hannibalic War” or “The Carthaginian War”, the war against Hannibal is the second major war between the Romans and Carthage, with the participation of Numidian-Berber armies and tribes favoring both sides. This war, which lasted from 218 to 201 BC, had three major conflicts that resulted in the battles of Trebia, Lake Trasimene, Cannae, Metaurus, and Zama. These were called the Punic Wars as Rome’s name for the Carthaginians was “Punici” due to their Phoenician ancestry.


The Conquest of the Aztec Empire


Hernán Cortés, a Spanish conquistador, began the invasion of the Aztecs in February of 1519 and was declared victorious on August 13, 1521. He formed an allegiance with some of the tributaries and enemies of the Aztecs including the Totonacs and the Tlaxcatecas. After eight months of battle with the Aztec emperor, Montezuma, Cortés took Tenochtitlan and made the emperor his puppet. Finally, after a while he had him killed and the population of the city stirred up a rebellion, but the Spaniards and the Tlaxcalans returned with better reinforcements and a plan to siege the city. The abolition of the Aztec Empire was a vital part of the formation of New Spain, although it was not formalized by the Monarchy until 1535.


The Thirty Years War


This war was not only the longest conflict in European history, but the most destructive as well as it involved most of the countries of Europe in an almost never-ending conflict. What first started as religious discord between the Protestants and Catholics grew to involve most of the great powers of that time, and inflamed things like the Bourbon-Hapsburg rivalry.


The War of the Spanish Succession


The conflict arose from the feared possible unification of the kingdoms of Spain and France under one Bourbon monarch, and was fought by the French Bourbons who supported Philip V and the Grand Alliance of the Austrian Hapsburgs who were loyal to Archduke Charles. The French Bourbons and the Austrian Hapsburgs were both related to King Charles II who was sick and had no heir to the throne. The battles of Blenheim, Ramillies, and Malplaquet ended with the treaties of Utrecht and Rastatt, which resulted in naming Philip V as King of Spain, but this also removed him from the French line of succession.


Napoleonic Wars


As the monarchy that ruled France collapsed with Napoleon Bonaparte being named its First Consul in 1799, this was seen as a threat to other European monarchies. The Napoleonic wars were a series of attempts to overthrow Napoleon’s revolutionary government and restore the monarchy to power. The conflicts with France led him to proclaim himself the Emperor in 1804 and also resulted in the dissolution of the Holy Roman Empire, the weakening of the Spanish Empire, and the emergence of Britain as one of the world’s powers. Though his battles ended in Waterloo in 1815, casualties were numbered to a staggering 3.5 million.


Taiping Rebellion


One of the largest and deadliest conflicts of the 19th centurty, this rebellion was led by Hong Xiuquan who was opposed to the  Manchu led Qing Dynasty. His campaign, however, was foiled when they enlisted the help of the French and British forces. After 15 years of rebellion, Xiuquan was finally defeated but left 20 million casualties in his wake.


The American Civil War


When Abraham Lincoln won the presidential election in 1860, he opposed the expansion of slavery into the territories and proposed its abolition. This led the seven cotton-based states to form the Confederate States of America hoping to gain the support of Europe. The civil war was fought between the Union of the North states and the Confederacy of the South. This is one of the first industrial wars involving railroads, telegraphs, steamships, and mass-produced weapons as well as one of the deadliest with an estimated casualty count of nearly 1 million.


Dungan Revolt


Also known as the Hui Minorities’ War, this was comprised of ten uprisings made by the Muslim Hui people of China  in the 19th century. While the rebellion was brought about by several interrelated events, the primary reason was the intention of establishing a Muslim emirate along the Yellow River. The revolts were unsuccessful however, and an estimated 12 million people lost their lives.


The Conquests of Timur


Timur was a conqueror in Central and Western Asia who only wanted one thing…power. He waged war and founded the Timuri Empire and the Timurid dynasty and was behind the massacre of 100,000 people in Delhi and 90,000 people in Baghdad. In total, his campaigns cost approximately 15 million people their lives.


The First Balkan War


This war was between the Balkan league, comprised of Serbia, Greece, Bulgaria, and Montenegro against the Ottoman Empire. Due to the immense number of the Balkan league armies, they were able to defeat the Ottoman Empire easily. This also led to the partitioning of the territories of the Ottoman Empire among the allies. However, Bulgaria was dissatisfied with the division of Macedonia, which started the Second Balkan War. These wars left a death toll of an estimated 100,000 people.


Russian Civil War


Just like the Napoleonic Wars, the Russian civil war was caused by a series of events that led to the execution of Nicolas II, the last Russian Tsar, and his entire family by the Bolsheviks. The death toll at the end of the war reached 20 million people encompassing 15 million lives lost during the rebellion, 1.5 million soldiers, and 250,000 executed as enemies of the people.


World War I


The First World War was triggered when Gavrilo Princip, a Yugoslav nationalist, assassinated the Arch Duke of Austria, Franz Ferdinand. The Great War was formed due to the alliances of world powers, and since they also have colonies, they were all drawn into the war. The battles were fought between the Allies and the Central powers. The war ended on Armistice Day in November 11, 1918 when Germany surrendered but the war left 16 million dead, with 5.7 million soldiers from the Allies and 4 million from the Central powers, the rest being civilians.


The Spanish Civil War


This war was between the Republicans who were loyal to the established Spanish republic, and against the Nationalists rebels, who were led by General Francisco Franco. The coup was supported by all military units and when the Nationalists prevailed, Franco ruled Spain for 36 years. Atrocities were committed by both sides and tens of thousands of civilians were killed.


World War II


Although World War I was considered the “war to end all wars” this was not so as it only planted seeds of discontent. World War II escalated when the German Nazis invaded Poland. This time the two camps were made up of the Allies and the Axis. Between bloody beach invasions, concentration camps, and nuclear weapons World War II is often considered the bloodiest war in history.


The Arab-Israeli Conflict


This was and still is the result of military tensions between the Arab League and Israelis who are disputing their territories after the collapse of the Ottoman Empire. Territories considered by the Israelis as their historical homeland were also claimed by the Palestinian Arabs. Despite various peace agreements throughout the years, skirmishes have still ensued.


Chinese Civil War


The civil war was the result of a revolt by the Koumintang of China against the ruling Communist Party. It cost millions of lives and following the defeat of the Koumintang resulted in two ruling states, the Republic of China (ROC) in Taiwan and the People’s Republic of China in the mainland, both claiming to be the legitimate government.


The Korean War


This war combined the tactics of both WW I and WW II with a mobile campaign of swift infantry attacks and air bombings. It took place was between the Republic of Korea in the South, and Democratic People’s Republic of Korea in the North. This resulted in the creation of the Korean Demilitarized Zone which divides the North and South near the 38th parallel.


Vietnam War


This is a Cold War military conflict that occurred not only in Vietnam, but also in Laos and Cambodia and ended with the fall of Saigon in 1975. The war was fought between North Vietnamese factions and their communist allies against the government of South Vietnam, which was supported by the United States and other anti-communist countries. The casualties were estimated at around 3 million.