The Mound Builders didn’t come into contact with European settlers.
By the eighteenth century, when whites began crossing the Appalachians into the Mississippians’ lands, their villages were gone. We can only guess at the Mound Builders’ fate.
Their great settlements may have been laid low by widespread disease or by other Native American invaders. Changes in climate may have caused droughts or flooding that destroyed their crops. Or maybe their villages were just too successful, with populations growing so large that they could not be sustained by the resources around them.
Their mounds, however, remained intact. White settlers were amazed by these great earthworks. Some, rightly, recognized that these monuments were made by earlier Native American peoples.
Certain whites wrongly assumed that the mounds were built by either Aztec Indians from present-day Mexico or by the lost tribes of Israel told of in the Bible.
These folks were so convinced of their superiority over the Native Americans around them that they could not believe their ancestors could have created these fantastic structures.