What were the earliest anthropological theories made about the toltec mounds

Toltec Mounds is recognized as one of the largest archaeological sites situated in the Mississippi River valley, covering roughly 100 acres and initially consisting of a total of 18 mounds. The exact name the Native inhabitants used for themselves remains unknown due to their lack of a written language. It appears they abandoned the site around 1050 A.D., and while the reasons for the construction of the mounds are not entirely clear, some clues have been uncovered. The mounds form a large rectangular area, known as the ceremonial plaza. Despite many mounds not surviving to the present day, those that have are quite substantial. When we reached the tallest mound, Mound A, our guide indicated its height of 49 feet. In contemporary terms, this may not appear significant, but in that era, without modern machinery like tractors and excavators, all material would have been moved manually, likely using a bowl. The effort and time needed to construct just one mound, let alone a total of 18, would have been tremendous.