The dominant interpretation in the nineteenth century and into the early twentieth was one that later archaeologists have called the “Mound Builder Myth” — the belief, widespread among non-Native Americans, that the mounds of the Mississippi Valley had been built not by the ancestors of contemporary Native people but by a separate, superior race that had subsequently vanished.

The Mound Builder Myth served specific ideological functions.

If the mounds had been built by Native people — the same Native people who were being dispossessed of their lands in the nineteenth century — then the mounds were evidence that Native people were capable of building complex civilizations, which complicated the narrative that dispossession was justified by Native people’s inability to “use” the land productively.

If the mounds had been built by a different, vanished people, then the Native people of the present were not the heirs of that achievement, and their land could be taken without the moral complications that acknowledging their civilization would introduce.