The tradition of celebrating the holiday on Thursday dates back to the early history of the Plymouth and Massachusetts Bay colonies, when post-harvest holidays were celebrated on the weekday regularly set aside as “Lecture Day,” a midweek church meeting where topical sermons were presented.
With a few deviations, Lincoln’s precedent was followed annually by every subsequent president—until 1939. In 1939, Franklin D. Roosevelt departed from tradition by declaring November 23, the next to last Thursday that year, as Thanksgiving Day.
Considerable controversy surrounded this deviation, and some Americans refused to honor Roosevelt’s declaration. For the next two years, Roosevelt repeated the unpopular proclamation, but on November 26, 1941, he admitted his mistake and signed a bill into law officially making the fourth Thursday in November the national holiday of Thanksgiving Day.