From Nanjing 1937: Battle for a Doomed City, by Peter Harmsen (Casemate, 2015), Kindle Loc. 357-375:
For all its modern buildings, signaling the creation of a new nation, Nanjing remained full of history. Even the city’s name, meaning “Southern Capital,” was testimony to its former function as the home of several dynasties. Ancient generals had built a fortress here as early as the fifth century B.C., and in the third century A.D., the rulers of the kingdom of Eastern Wu had set up their capital in the city. More than a millennium later, the first Ming emperors had built their palaces in Nanjing before moving to Beijing to be closer to the northern border and better able to manage the age-old threat of invaders entering the empire from beyond the Great Wall.
At times, for instance at the beginning of the Ming Dynasty in the late 14th century, Nanjing had been so powerful that it outshone any other contemporary city on the planet, but at other times it had seen humiliation and deprivation on an unimaginable scale. Like China as a whole, it had been conquered repeatedly, and twice it had been nearly annihilated. In the late sixth century, a hostile army had entered, butchered the inhabitants, torn down every building, and plowed up the ground to remove any sign of the city’s former splendor. The second time it had been almost completely destroyed was in the 1860s when it had been at the center of the world’s bloodiest conflict of the 19th century.
The city had been the capital of the Taiping rebels, who had been driven by a quasi-Christian ideology to seek to overthrow the emperor in Beijing. When the emperor’s armies struck back, the result was a civil war that caused the deaths of at least 20 million people. The savage climax to this conflict was in Nanjing, which fell in 1864. Loyalist imperial troops besieged the city and when they eventually broke the back of resistance and entered, they engaged in an orgy of death and destruction.
The elderly and the children, who were of no use as labor, were especially targeted and slaughtered. “Children and toddlers, some not even two years old, had been hacked up or run through just for sport,” wrote a Chinese official who entered the city shortly after the end of the massacre. In its unsophisticated brutality the bloodletting seemed to belong to a more primitive age but, remarkably, in 1937 it was still within living memory. Residents who had been young in the 1860s were now toothless octogenarians whose sad eyes had seen too much.