Some of the traditional view of the viciousness of Aztec culture comes from very high estimates of the amount of human sacrifice in Tenochtitlan (20,000 victims/year, 50,000 victims/year, 100,000+ victims/year).
When Montezuma Met Cortés does a good job dismantling these estimates in its third chapter. If the Aztecs were sacrificing tens of thousands of people each year in Tenochtitlan, where are all the bones?
On p. 173-5 of my copy:
One illuminating and fascinating new source of evidence is the Great Temple itself. No records survived of its destruction in the 1520s, and it remained buried for centuries; yet the Great Temple was precisely where almost all the executions, most notably the alleged mass sacrifices, took place. However, in 1978 Mexican archaeologists began to excavate the foundations of the Great Temple – that is, the pyramid upon which the twin temples stood, and its surrounding structures.
Directed for four decades by Eduardo Matos Moctezuma, the project has gradually revealed that the Great Temple was rebuilt seven times, helping to preserve more than 126 caches of ritual offerings buried by generations of Aztec priests ... what of the bones of the hundreds of thousands of alleged victims of Aztec brutality? Or, if we believe that the empire was “a cannibal kingdom” and those victims were all taken off to be eaten in Aztec homes, what of the human skulls “too numerous to count” that Díaz later claimed he had seen in the square facing the Great Temple?
The archaeologists did indeed uncover two large carved stones, which more or less match conquistador descriptions as those upon which prisoners were executed. They also found ritual knives, most of flint, finely carved and decorated, deposited over many years. In addition, the floors of some buildings, and remnants of some altars and statues, contained traces of human blood. Human remains were also found, those of 126 people; forty-two were children. The children all suffered from disease, and their throats had been cut. Forty-seven adult heads were found, spread through various offerings from different time periods.
But none of those adults had been decapitated. Of Díaz’s skulls, perforated to fit onto skull racks, only three were found prior to 2015 (three skulls from almost four decades of excavations). More than ten times that many decorated facial skull masks were found under the Great Temple floors. Even when archaeologists found the larger of the two skull racks, the huey tzompantli, in 2015, it revealed scores – but not hundreds, let alone thousands – of human skulls, with those outnumbered by two-dimensional carved stone skulls. Furthermore, the ritual knives do not appear to have been used; they were symbolic offerings.
Archaeologists have found more human remains at Teotihuacan than in Tenochtitlan (Teotihuacan is the spectacular site north of Tenochtitlan whose heyday was a millennium before that of the Aztecs). Of the eighty thousand prisoners supposedly sacrificed over four days in 1486, “no evidence approaching one-hundredth of that number has been found in the excavations”; put another way, compared to Zumárraga’s imaginary 2 million children executed during the century before Spaniards invaded, the Great Temple yielded evidence of 0.0021 percent that many.”
So the Aztecs were probably much less enthusiastic about ritual sacrifice than we imagine.