PREVIOUSLY: What really made it the story is that a publication mentioning that dinner published by the Rev . Alexander Young included a footnote that said , “ This was the first Thanksgiving, the great festival of New England . ” People picked up on this footnote . The idea became pretty widely accepted , and Abraham Lincoln declared it a holiday during the Civil War to foster unity . It gained purchase in the late 19th century , when there was an enormous amount of anxiety and agitation over immigration . The white Protestant stock of the United States was widely unhappy about the influx of European Catholics and Jews , and wanted to assert its cultural authority over these newcomers . How better to do that than to create this national founding myth around the Pilgrims and the Indians
