2. While the first Thanksgiving dates back to the Pilgrims, it was many years after that Thanksgiving in 1621 that the day become a national holiday. In 1789, President George Washington recommended to the American public that Nov. 26 be a day of prayer, especially in appreciation of the ability of the newly "freed" Americans to develop their own government.
3. However, not all of the American public bought into this idea and thus it wasn't observed as a holiday until President Abraham Lincoln proclaimed the last Thursday of November to be Thanksgiving in 1863. Many people credit magazine editor Sarah Josepha Hale for persuading Lincoln. Hale used her magazine and letters sent to many political and otherwise influential people to campaign for this holiday.
4. Around 1939, President Franklin Roosevelt moved Thanksgiving forward, to the fourth Thursday of November, which is how it's celebrated today.