Mississippian people were of significantly larger physical stature than the Europeans explorers who encountered them, but they had no immunities to the explorers' diseases. Disease and violent encounters alike hastened the decline of the Mississippian Culture. William Barton, a naturalist, wrote in 1775 of the mounds built by these people:
It is altogether unknown to us what could have induced the Indians to raise such a heap of earth in this place . . . It is reasonable to suppose, however, that they were to serve some important purpose in those days, as they were public works, and would have required the united labor and attention of a whole nation ("Moundbuilders- North Georgia's Early Inhabitants").
As noted, the first European settlers in the region were Spanish missionaries and English traders, and this was a turbulent and tragic era marked by plagues and slave raiding that destroyed the indigenous kingdoms even as Spain and England fought their own war, conducted by proxy, for the southeastern borderlands. It was this era which set the stage for the establishment of Georgia by James Edward Oglethorpe
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