We owe the modern concept of Thanksgiving to a woman named Sarah Josepha Hale. Hale, editor of Godey's Lady's Book and author of the famous "Mary Had a Little Lamb" nursery rhyme, who spent 40 years advocating for a national, annual Thanksgiving holiday.
In the years leading up to the Civil War, she saw the holiday as a way to infuse hope and belief in the nation and the Constitution. So, when the United States was torn in half during the Civil War and President Abraham Lincoln was searching for a way to bring the nation together, he discussed the matter with Hale.
Lincoln Sets Date
On October 3, 1863, Lincoln issued a Thanksgiving Proclamation that declared the last Thursday in November (based on Washington's date) to be a day of "thanksgiving and praise." For the first time, Thanksgiving became a national, annual holiday with a specific date.
FDR Changes It
For 75 years after Lincoln issued his Thanksgiving Proclamation, succeeding presidents honored the tradition and annually issued their own Thanksgiving Proclamation, declaring the last Thursday in November as the day of Thanksgiving. However, in 1939, President Franklin D. Roosevelt did not.
In 1939, the last Thursday of November was going to be November 30. Retailers complained to FDR that this only left 24 shopping days to Christmas and begged him to push Thanksgiving just one week earlier. It was determined that most people do their Christmas shopping after Thanksgiving and retailers hoped that with an extra week of shopping, people would buy more.
So when FDR announced his Thanksgiving Proclamation in 1939, he declared the date of Thanksgiving to be Thursday, November 23, the second-to-last Thursday of the month.
What Happened to Thanksgiving the Following Year?
In 1940, FDR again announced Thanksgiving to be the second-to-last Thursday of the month. This time, 31 states followed him with the earlier date and 17 kept the traditional date. Confusion over two Thanksgivings continued.
Congress Fixes It
Lincoln had established the Thanksgiving holiday to bring the country together, but the confusion over the date change was tearing it apart. On December 26, 1941, Congress passed a law declaring that Thanksgiving would occur every year on the fourth Thursday of November.