Summary: Learn how Franklin D. Roosevelt changed Thanksgiving in this free holiday origins video from an American history authority and Turkey Day expert.
"Hello, I'm Matt Cail and on behalf of Expert Village, I'm here today to tell you all about the history of Thanksgiving. Thanksgiving was usually proclaimed to be the last Thursday of November, at least towards the tail end of November. While the actual date oscillated a bit, it was generally near the, closer toward the end of November rather than ever towards the middle of the month. But again, since Thanksgiving relied on a proclamation by the president, this could change and it did. In the, underneath the tenure of FDR, FDR was president starting 1932 and going through the mid 1940's and in like the 1939, 40 period, 41, those years, FDR started to mess with Thanksgiving. And by messing with Thanksgiving, he decided to push it back about a week, more towards the middle of November rather than near the tail end. The reasoning behind this was they'd make the Christmas season a little longer and to try to bump up business's Christmas sales. A lot of people saw this for what it is and there was a backlash. There was an uproar against FDR moving Thanksgiving so much so that in 1941 Congress declared Thanksgiving a national holiday and basically set it towards the Thursday near the end of November so that there would be no more date games played with Thanksgiving and it would no longer rely on the president declaring it a national holiday or observance."
eHow Article: Thanksgiving History of Roosevelt Moving Date