On this day in 763, the devastating An Lushan Rebellion against the Tang Dynasty of China came to an end. Sanning seven years and three emperors, the revolt was led by General An Lushan, who declared himself emperor and established the rival Yan Dynasty in the north. The scale of the conflict was beyond the norm for most of the medieval world, involving the mobilization of 800,000 to 1 million troops in total.
Estimates of the death toll vary wildly, from 13 million to 36 million; because China accounted for about a third of the world’s population at the time, the higher figure — which is admittedly controversial — would represent one-sixth of all humans, making the An Lushan Rebellion proportionally the deadliest conflict ever (and even in absolute terms it remains in the top ten).
The world’s second-bloodiest conflict in total loss of life is another Chinese civil war, that of the Three Kingdoms era, which spanned almost one hundred years during the 2nd and 3rd century. Anywhere from 36-40 million people were killed, a number that would not be surpassed until WWII in the mid-20th century (though some estimates put the Mongol Conquests of the 13th-14th century at around the same amount as the Three Kingdoms).
A contemporary list of history’s biggest wars is dominated by China, including WWII (in which the country suffered 14-20 million casualties, second only to Russia), the aforementioned Mongol Conquests, the Taiping Rebellion of the mid-19th century (20-100 million deaths), and the 17th century conquest of the Ming Dynasty by the Qing (25 million).