Apparently the removal of the continent of Atlantis, the central source of the empire's power, weakened it somewhat; but still the Mound-Builder empire held its own against the Algonquin peoples who were pressing on their borders from the coast-lands to the north and northeast. This pressure was resisted as long as the Mound-Builders were able to maintain themselves united; but, after a time, for some reason, this empire deteriorated. Algonquin tradition explains it by the priestcraft among the Mound-Builders' gaining such despotic control that they were able to institute extensive sacrifices
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