This Day in History: br FDR Establishes thebr Modern Thanksgiving Holiday November 26, 1941 President Franklin D. Roosevelt br signed a bill officially establishing br the fourth Thursday in November as Thanksgiving Day. In 1939, Roosevelt had departed br from tradition by declaring the nextbr to last Thursday that year br as Thanksgiving Day. The tradition dated back to br President Abraham Lincoln, br who declared Thanksgiving to br fall on the last Thursday of November. Franklin's deviation sparked br considerable controversy, with br some Americans refusing to honor br the declaration. But Roosevelt repeated br the unpopular proclamation br for the next two years. In 1941, the president admitted br his mistake and signed the bill br establishing the modern national br holiday of Thanksgiving Day.