3. The Conquests of the Mongol Empire, spanning more than a century, resulted in the deaths of tens of millions in the course of constructing the largest contiguous empire in human history
Beginning in 1206, Genghis Khan, having united the Mongol people under a single banner for the first time in history, unleashed his new empire upon the world. Starting with the invasion of Western Xia, by 1209 the victorious Mongol hordes descended upon their ancient enemy: China. In 1211 the Mongols invaded Jin China, capturing and sacking the capital city of Yanjing. Pivoting to the West after the execution of his ambassadors by the Khwarezmid Empire, Genghis invaded Khwarezmia in 1919; taking just two years to conquer the Central Asian nation, the Mongols slaughtered at least 25% of the local population who suffered approximately 2,000,000 fatalities.
Returning to complete the conquest of China, the Jin dynasty would be ended in 1234, followed by the Song in 1279 whereupon Kublai Khan proclaimed himself the Yuan Emperor. In the interim years, the Mongols, under the leadership of Ögedei Khan, invaded Eastern Europe, defeating Bulgaria, Hungary, Poland, Russia, and Serbia, in addition to solidifying control over the Middle East after the sack of Baghdad in 1258. In total, across more than a century of warfare the Mongols are believed to have been directly responsible for the deaths of 30,000,000 to 40,000,000 people, in addition to displacing hundreds of millions and indirectly causing the calamitous Black Plague in Europe.
2. The Three Kingdoms, during which period China existed in a state of continuous warfare, saw an estimated 40,000,000 lose their lives
The Three Kingdoms was a period of division within mainland China between the competing states of Wei, Shu, and Wu, lasting from 184 to 280. Beginning with the deterioration and eventual collapse of the Han dynasty, and concluding with the ascendance of the Jin, each rival faction claimed dominion over the others as the sole legitimate emperor. Eventually, after decades of war, in 263 the Shu was conquered by the Wei. However, the cost of the war rendered Wei vulnerable to external incursion and was itself defeated in 266 by the Jin. Unable to stand alone against the combined might of the enlarged Jin, Wu was conquered by the Jin in 280 ending the conflict.
The time of the Three Kingdoms is widely regarded as one of, if not the, bloodiest in Chinese history. A census taken in 280 following the reunification of the region under the Jin accounts for 2,459,840 households, encompassing 16,163,863 total subjects. This seemingly large figure was merely a shadow of the population during the preceding Han dynasty, under which 10,677,960 households included at least 56,486,856 individuals – a decline of more than 40,000,000 over the hundred year conflict.
1. World War II, the deadliest war in human history, was responsible for the deaths of as many as 85,000,000 people in just six years
World War II, the largest and deadliest war in human history, was a global total war between 1939 and 1945, involving more than 30 countries and 100 million participants. Traditionally dated as beginning on September 1, 1939, following the invasion of Poland by Nazi Germany and the subsequent declarations of war by the United Kingdom and France in retaliation, the war rapidly expanded to engulf the majority of the world. Spanning multiple theaters of war, including Western and Eastern Europe, North Africa, and the Pacific, the Second World War saw France occupied by Germany in 1940, Japan attack the United States in 1941, and Russia betrayed by Germany only to rally and ultimately capture Berlin in 1945.
Although not even close to the longest war in history, the consequences of World War II were both lasting and devastating. Encompassing the creation and first use of atomic weapons, the mass industrial extermination of humans during the Holocaust, in addition to combat fatalities and widespread starvation, the Second World War is estimated to have been responsible for the deaths of 50,000,000 to 85,000,000. Despite concluding in the unconditional surrender of the Axis to the Allies, tensions did not abate; instead, the emergence of the United States and Soviet Union as rival superpowers merely provided the foundations for the half-century Cold War that was to follow.
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