A recent discovery of a tower of hundreds human skulls in Mexico City, in what was once the Aztec capital of Tenochtitlan, has drawn attention to the idea that, according to the Spanish conquistadores, the Mayas and the Aztecs ritually sacrificed human beings as offerings to the sun. The towers struck fear into the hearts of the Spanish when they saw them, but are they really evidence of human sacrifice?

Elizabeth Graham, a Professor of Mesoamerican archaeology at University College, London, views the skulls as “spoils of war.” In many places in the world – Japan, medieval Europe, and England – people cut off the heads of their enemies. This, she adds, was symbolic of conquest. For Graham the skulls are evidence of property and ownership. The display of skulls served as evidence that people had a right to the property they had accumulated. There was ample reason for the Spanish to label the various Mesoamerican groups as practitioners of human sacrifice.

Because human sacrifice was broadly practiced in all areas of the world at one point or another, there is a certain kind of virtue attached to those cultures that we think never engaged in it. In particular, people tend to think of ancient Jews and the Romans as two groups that deplored human sacrifice and outlawed it in their religious and political codes. To an extent, there’s some truth to this: when, in the book of Genesis, Abraham prepares to sacrifice his son Isaac to God, an angel intervenes and provides a ram in the place of Abraham’s favorite child. Certainly, by the time they returned from exile in Babylon in the sixth century BCE, Jews were sacrificing exclusively animals. The prohibitions on child sacrifice found in the Hebrew Bible set them apart from other groups (like worshippers of Baal) who were known for sacrificing young, usually male, infants in the hope of securing divine favor.